Ontogenesis of the sperm whale brain
Corresponding Author
Helmut H.A. Oelschläger
Department of Anatomy, Johann Wolfgang Goethe-University Frankfurt am Main, 60590 Frankfurt am Main, Federal Republic of Germany
Department of Anatomy (Dr. Senckenbergische Anatomie) der Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Federal Republic of GermanySearch for more papers by this authorBirgit Kemp
Department of Obstetrics and Gynecology, Rheinisch-Westfälische Technische Hochschule, 52074 Aachen, Federal Republic of Germany
Search for more papers by this authorCorresponding Author
Helmut H.A. Oelschläger
Department of Anatomy, Johann Wolfgang Goethe-University Frankfurt am Main, 60590 Frankfurt am Main, Federal Republic of Germany
Department of Anatomy (Dr. Senckenbergische Anatomie) der Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Federal Republic of GermanySearch for more papers by this authorBirgit Kemp
Department of Obstetrics and Gynecology, Rheinisch-Westfälische Technische Hochschule, 52074 Aachen, Federal Republic of Germany
Search for more papers by this authorAbstract
The development of the sperm whale brain (Physeter macrocephalus) was investigated in 12 embryos and early fetuses to obtain a better understanding of the morphological and physiological adaptations in this most exotic cetacean concerning locomotion, deep diving, and orientation. In male adult sperm whales, the average absolute brain mass and the relative size of the telencephalic hemisphere are the largest within the mammalia, whereas the ratio of the brain mass to the total body mass is one of the smallest.
In the early sperm whale fetus, the rostral part of the olfactory system (olfactory nerves and bulbs) is lost, whereas the nervus terminalis seems to persist. Several components of the limbic system show signs of regression (hippocampus, fornix, mamillary body). In contrast, some components of the auditory system (trapezoid body, inferior colliculus) show marked enlargement in the early fetal period, thereby reflecting their dominant position in the adult. The cerebellum and pons grow slower than in most smaller toothed whales. The pyramidal tract develops poorly (reduction of the limbs), whereas marked growth of the striatum and inferior olive may be related to the animal's locomotion via trunk and tail.
In the early fetal period, the trigeminal, vestibulocochlear, and facial nerves are the dominant cranial nerves (besides the vagus nerve). Whereas the number of axons in the vestibulocochlear nerve is high in adult, toothed whales and their diameters are considerable, the trigeminal nerve of the sperm whale may be the thickest of all cranial nerves and has the largest number of axons (innervation of the huge forehead region). A similar situation seems to exist for the facial nerve: It innervates the blowhole musculature that surrounds the very large spermaceti organ and melon (generation and emission of sonar clicks). J. Comp. Neurol. 399:210–228, 1998. © 1998 Wiley-Liss, Inc.
Literature Cited
- Addison, W. H. F. (1915) On the rhinencephalon of Delphinus delphis L. J. Comp. Neurol. 25: 497–522.
- Born, G. (1883) Die Plattenmodellirmethode. Arch. Mikrosk. Anat. 22: 584–599.
10.1007/BF02952679 Google Scholar
- Breathnach, A. S. (1953) The olfactory tubercle, prepyriform cortex and precommissural region of the porpoise (Phocoena phocoena). J. Anat. 87: 96–113.
- Breathnach, A. S. (1955) The surface features of the brain of the humpback whale (Megaptera novaeangliae). J. Anat. 89: 343–354.
- Breathnach, A. S. (1960) The cetacean nervous system. Biol. Rev. Cambridge Philos. Soc. 35: 187–230.
- Breathnach, A. S. and F., Goldby (1954) The amygdaloid nuclei, hippocampus and other parts of the rhinencephalon in the porpoise (Phocoena phocoena). J. Anat. 88: 267–291.
- Brodal, A. and B., Hoivik (1964) Site and mode of termination of primary vestibulocerebellar fibres in the cat. An experimental study with silver impregnation methods. Arch. Ital. Biol. 102: 1–21.
- Bruesch, S. R. and L. B. Arey (1942) The number of myelinated and unmyelinated fibers in the optic nerve of vertebrates. J. Comp. Neurol. 77: 631–665.
- Buhl, E. H. (1986) Entwicklungsgeschichte des Zentralnervensystems bei den Zahnwalen (Odontoceti) unter besonderer Berücksichtigung des Schweinswals Phocoena phocoena (Linnaeus, 1758) [thesis]. Frankfurt am Main: Faculty of Human Medicine, University of Frankfurt am Main.
- Buhl, E. H. and H. A., Oelschläger (1986) Ontogenetic development of the N. terminalis in toothed whales. Evidence for its nonolfactory nature. Anat. Embryol. 173: 285–295.
- Buhl, E. H. and H. A., Oelschläger (1988) Morphogenesis of the brain of the harbour porpoise. J. Comp. Neurol. 277: 109–125.
- Clarke, M. R., H. R., Martins, and P. Pascoe (1993) The diet of sperm whales (Physeter macrocephalus Linnaeus, 1758) off the Azores. Phil. Trans. R. Soc. London B 339: 67–82.
- Cranford, T. (1988) The anatomy of acoustic structures in the spinner dolphin forehead as shown by x-ray computed tomography and computer graphics. In P. E. Nachtigall and P. W. B. Moore (eds): Animal Sonar: Processes and Performance. NATO A0SI Series A, Vol. 156. New York: Plenum Press, pp. 67–77.
- Cranford, T. (1992) Functional Morphology of the Odontocete Forehead: Implications for Sound Generation [Ph.D. thesis]. Santa Cruz, CA: University of California, Santa Cruz.
- Cranford, T. W., M., Amundin, and K. S. Norris (1996) Functional morphology and homology in the odontocete nasal complex. Implications for sound generation. J. Morphol. 228: 223–285.
10.1002/(SICI)1097-4687(199606)228:3<223::AID-JMOR1>3.0.CO;2-3 CASPubMedWeb of Science®Google Scholar
- Dailly, M. (1972a) Contribution to the study of the cochlear apparatus in dolphins. In G. Pilleri (ed): Investigations on Cetacea, Vol. 4. Berne, Switzerland: Brain Anatomy Institute, pp. 215–230.
- Dailly, M. (1972b) Contribution to the study of the VIIIth vestibular nerve of cetaceans: The elliptic nucleus. In G. Pilleri (ed): Investigations on Cetacea, Vol. 4. Berne, Switzerland: Brain Anatomy Institute, pp. 231–248.
- Dawson, W. W., G. M., Hope, R. J. Ulshafer, M. N. Hawthorne, and R. L. Jenkins (1983) Contents of the optic nerve of a small cetacean. Aquatic Mamm. 10: 45–56.
- de Graaf A. S., (1967) Anatomical Aspects of the Cetacean Brain Stem. Assen: Van Gorcum and Prakke.
- Dral, A. D. G. (1987) On the optics of the dolphin eye. Aquatic Mamm. 13: 61–64.
- Duffield, D. W., J. T., Haldiman, and W. G. Henk (1992) Surface morphology of the forebrain of the bowhead whale, Balaena mysticetus. Marine Mamm. Sci. 8: 354–378.
- Evans, P. G. H. (1987) The Natural History of Whales and Dolphins. New York: Facts on File Publications.
- Filimonoff, I. N. (1965) On the so-called rhinencephalon in the dolphin. J. Hirnforsch. 8: 1–23.
- Gambell, R. (1994) Physeter catodon Linnaeus, 1758. In J. Niethammer and F. Krapp (eds): Handbuch der Säugetiere Europas, Vol. 6: Meeressäuger, Teil I: Wale und Delphine-Cetacea. Wiesbaden: Aula-Verlag, pp. 625–646.
- Gans, A. (1916) Die Pyramidenbahn der Phocaena. Anat. Anz. 49: 281–284.
- Gao, G. and K., Zhou (1991) The number of fibers and range of fiber diameters in the cochlear nerve of three odontocete species. Can. J. Zool. 69: 2360–2364.
- Gao, G. and K., Zhou (1992) Fiber analysis of the optic and cochlear nerves of small cetaceans. In J. A. Thomas, R. A. Kastelein, and A. Y. Supin (eds): Marine Mammal Sensory Systems. New York: Plenum Press, pp. 39–52.
- Gao, G. and K., Zhou (1995) Fiber analysis of the vestibular nerve of small cetaceans. In R. A. Kastelein, J. A. Thomas, and P. E. Nachtigall (eds): Sensory Systems of Aquatic Mammals. Woerden: De Spil Publishers, pp. 447–453.
- Garey, L. H., E., Winkelmann, and K. Brauer (1985) Golgi and Nissl studies of the visual cortex of the bottlenose dolphin. J. Comp. Neurol. 240: 305–321.
- Gaunt, W. A. (1971) Microreconstruction. London: Pitman Medical.
- Glezer, I. I. and P. J., Morgane (1990) Ultrastructure of synapses and Golgi analysis of neurons in neocortex of the lateral gyrus (visual cortex) of the dolphin and pilot whale. Brain Res. Bull. 24: 401–427.
- Glezer, I. I., M. S., Jacobs, and P. J. Morgane (1988) Implications of the “initial brain” concept for the brain evolution in cetacea. Behav. Brain Sci. 11: 75–116.
- Glezer, I. I., P. R., Hof, V. V. Istomin, and P. J. Morgane (1995) Comparative immunocytochemistry of calcium-binding protein-positive neurons in visual and auditory systems of cetaceen and primate brains. In R. A. Kastelein, J. A. Thomas, and P. E. Nachtigall (eds): Sensory Systems of Aquatic Mammals. Woerden: De Spil Publishers, pp. 476–513.
- Gribnau, A. A. M. and L. G. M., Geijsberts (1985) Morphogenesis of the brain in staged rhesus monkey embryos. Adv. Anat. Embryol. Cell Biol. 91: 1–69.
- Hamilton, W. J., J. D., Boyd, and H. W. Mossman (1976) Human Embryology, 4th ed. London: MacMillan Press.
- Hatschek, R. and H., Schlesinger (1902) Der Hirnstamm des Delphins (Delphinus delphis). In H. Obersteiner (ed):. Arb. Neurol. Inst. Wiener Univ. 9: 1–117.
- Haug, H. (1970) Der makroskopische Aufbau des Großhirns. Ergebn. Anat. Entwicklungsgesch. 43: 1–69.
- Hochstetter, F. (1919) Beiträge zur Entwicklungsgeschichte des mensclichen Gehirns. I. Teil. Wien und Leipzig: F. Deuticke.
- Hochstetter, F. (1929) Beiträge zur Entwicklung des menschlichen Gehirns. 2. Teil: Die Entwicklung des Mittelund Rautenhirns. Wien: F. Deuticke.
- Holzmann, T. (1991) Morphologie und Mikroskopische Anatomie des Gehirns beim Fetalen Narwal, Monodon monoceros [thesis]. Frankfurt am Main: Faculty of Human Medicine, University of Frankfurt am Main.
- Hosokawa, H., S., Igarashi, T. Kamiya, and K. Hirosawa (1969) Morphological characteristics and myelinization of the acoustic system in the dolphin (Stenella coeruleoalba). Sci. Rep. Whales Res. Inst. Tokyo 21: 95–123.
- Hughes, A. and H., Wässle (1976) The cat optic nerve: Fiber total count and diameter spectrum. J. Comp. Neurol. 169: 171–184.
- Jacobs, M. S. and A. V., Jensen (1964) Gross aspects of the brain and a fiber analysis of cranial nerves in the great whale. J. Comp. Neurol. 123: 55–72.
- Jacobs, M. S., P. J., Morgane, and W. L. McFarland (1971) The anatomy of the brain of the bottlenose dolphin (Tursiops truncatus). Rhinic lobe (rhinencephalon). 1. The palaeocortex. J. Comp. Neurol. 141: 205–272.
- Jacobs, M. S., W. L., McFarland, and P. J. Morgane (1979) The anatomy of the brain of the bottlenose dolphin (Tursiops truncatus). Rhinic lobe (rhinencephalon): II. The archicortex. Brain Res. Bull. 4 (Suppl): 1–107.
- Jansen, J. (1950) The morphogenesis of the cetacean cerebellum. J. Comp. Neurol. 93: 341–400.
- Jansen, J. (1952) On the whale brain with special reference to the weight of the brain of the fin whale (Balaenoptera physalus). Norsk Hvalfangst-Tid. 9: 480–486.
- Jansen, J. and J. K. S., Jansen (1953) A note on the amygdaloid complex in the fin whale (Balaenoptera physalus L.). Hvalrad. Skrift. 39: 1–14.
- Jansen, J. and J. K. S., Jansen (1969) The nervous system of cetacea. In H. T. Andersen (ed): The Biology of Marine Mammals. London: Academic Press, pp. 175–252.
- Jelgersma, G. (1934) Das Gehirn der Wassersäugetiere. Leipzig: J.A. Barth. Kamiya, T. and P. Pirlot (1974) Brain morphogenesis in Stenella coeruleoalba. Sci. Rep. Whales Res. Inst. Tokyo 26: 245–253.
- Kemp, B. (1991) Morphogenese des Säugetiergehirns am Beispiel des Pottwals unter besonderer Berücksichtigung der menschlichen Ontogenese [thesis]. Frankfurt am Main: Faculty of Human Medicine, University of Frankfurt am Main.
- Kemp, B. and H. A., Oelschläger (1998) Evolutionary Strategies of Odontocete Brain Development [Historical Biology], Chur, Switzerland (in press).
- Ketten, D. R. (1991) The marine mammal ear: Specialization for aquatic audition and echolocation. In D. B. Webster, R. R. Fay, and A. N. Popper (eds): The Evolutionary Biology of Hearing. Heidelberg: Springer-Verlag, pp. 717–750.
- Ketten, D. R. and D., Wartzok (1990) Three-dimensional reconstructions of the dolphin ear. In J. A. Thomas and R. A. Kastelein (eds): Sensory Abilities of Cetaceans: Laboratory and Field Evidence. NATO ASI Series, Vol. 196. New York: Plenum Press, pp. 81–105.
- Klima, M. (1987) Morphogenesis of the nasal structures of the skull in toothed whales (Odontoceti). In H. J. Kuhn and K. Zeller (eds): Morphogenesis of the Mammalian Skull. Mammalia Depicta. Beih. Z. Säugetierk. 13: 105–121.
- Klima, M. (1990) Histologische Untersuchungen an Knorpelstrukturen im Vorderkopf des Pottwals Physeter macrocephalus. Gegenbaurs Morph. Jahrb. Leipzig 136: 1–16.
- Klima, M. and H. A., Oelschläger (1994) Phylogenie und Systematik der Cetacea. In J. Niethammer and F. Krapp (eds): Handbuch der Säugetiere Europas, Vol. 6, Meeressäuger, Teil I A: Wale und Delphine-Cetacea ( D. Robineau, R. Duguy, and M. Klima eds). Wiesbaden: Aula-Verlag, pp. 31–48.
- Klima M. and P. J. H. van Bree (1985) Überzählige Skeletelemente im Nasenschädel von Phocoena phocoena und die Entwicklung der Nasen-region bei den Zahnwalen. Gegenbaurs Morph. Jahrb. Leipzig 131: 131–178.
- Klima, M., M., Seel, and P. Deimer (1986) Die Entwicklung des hochspezialisierten Nasenschädels beim Pottwal (Physeter macrocephalus). Gegenbaurs Morph. Jahrb. Leipzig 132: 245–284.
- Kojima, T. (1951) On the brain of the sperm whale (Physeter catodon L.). Sci. Rep. Whales Res. Inst. Tokyo 6: 49–72.
- Korneliussen, H. K. and J., Jansen (1964) The morphogenesis and structure of the inferior olive of Cetacea. J. Hirnforsch. 7: 301–314.
- Kröger, R. H. H. (1989) Dioptrik, Funktion der Pupille und Akkommodation bei Zahnwalen [thesis]. Tübingen: Faculty of Biology, University of Tübingen.
- Kükenthal, W. and T., Ziehen (1893) Über das Zentralnervensystem der Cetaceen nebst Untersuchungen über die vergleichende Anatomie des Gehirns bei Placentaliern. Denkschr. Med.-Naturw. Ges., Jena 3: 80–112.
- Ladygina, T. F. and A. Y., Supin (1978) On the homology of the different regions of the brain's cortex of Cetacea and other mammals. In V. E. Sokolov (ed): Morskiye Mlekopita'yushchiye, Resul'taty i Metodi Issledovanii [in Russian]. Moscow: Izdatel'stvo Nauka, pp. 55–64.
- Langworthy, O. R. (1932) A description of the central nervous system of the porpoise (Tursiops truncatus). J. Comp. Neurol. 54: 437–499.
- Leonhardt, H. and W., Lange (1987) Graue und weiße Substanz des Hirnstammes (Rautenhirn). In H. Leonhardt, B. Tillmann, G. Töndury, and K. Zilles (eds): Rauber/Kopsch: Anatomie des Menschen, Vol. 3, Nervensystem, Sinnesorgane. Stuttgart: Thieme-Verlag, pp. 259–318.
- Lockard, I. (1977) Desk Reference for Neuroanatomy. A Guide to Essential Terms. New York: Springer-Verlag.
- Marsh, J. T. and F. G., Worden (1964) Auditory potentials during acoustic habituation: Cochlear nucleus, cerebellum and auditory cortex. Electroenceph. Clin. Neurophysiol. 17: 685–692.
- McFarland, W. L., P. J., Morgane, and M. S. Jacobs (1969) Ventricular system of the brain of the dolphin, Tursiops truncatus, with comparative anatomical observations and relations to brain specializations. J. Comp. Neurol. 135: 275–368.
- Morgane, P. J. and M. S., Jacobs (1972) Comparative anatomy of the cetacean nervous system. In R. J. Harrison (ed): Functional Anatomy of Marine Mammals. London: Academic Press, pp. 117–244.
- Morgane, P. J., M. S., Jacobs, and W. L. McFarland (1971) The anatomy of the brain of the bottlenose dolphin (Tursiops truncatus). Rhinic lobe (rhinencephalon): The palaeocortex. J. Comp. Neurol. 141: 205–284.
- Morgane, P. J., M. S., Jacobs, and W. L. McFarland (1979) The anatomy of the brain of the bottlenose dolphin (Tursiops truncatus). Rhinic lobe (rhinencephalon): The archicortex. Brain Res. Bull. 4: 1–114.
- Morgane, P. J., M. S., Jacobs, and W. L. McFarland (1980) The anatomy of the brain of the bottlenose dolphin (Tursiops truncatus). Surface configurations of the telencephalon of the bottlenose dolphin with comparative anatomical observations in four other cetacean species. Brain Res. Bull. 5: 1–107.
- Morgane, P. J., W. L., McFarland, and M. S. Jacobs (1982) The limbic lobe of the dolphin brain: A quantitative cytoarchitectonic study. J. Hirnforsch. 23: 465–552.
- Morgane, P. J., M. S., Jacobs, and A. Galaburda (1986a) Evolutionary morphology of the dolphin brain. In R. J. Schusterman, J. A. Thomas, and F. G. Wood (eds): Dolphin Cognition and Behaviour–A Comparative Approach. London: Lawrence Erlbaum Assoc., pp. 5–29.
- Morgane, P. J., M. S., Jacobs, and A. Galaburda (1986b) Evolutionary aspects of the cortical organization in the dolphin brain. In R. J. Harrison and M. Bryden, (eds): Research on Dolphins. Oxford: Oxford University Press, pp. 71–98.
- Nachtigall, P. E. (1986) Vision, audition and chemoreception in dolphins and other marine mammals. In R. J. Schusterman, J. A. Thomas, and F. G. Wood (eds): Dolphin Cognition and Behaviour–A Comparative Approach. London: Lawrence Erlbaum Assoc., pp. 79–113.
- Nomina Anatomica (1983) 11th International Congress of Anatomy (1980, Mexico City), International Anatomical Nomenclature Committee, 5th ed. Baltimore: Williams and Wilkins.
- Norris, K. S. (1964) Some problems of echolocation in cetaceans. In W. N. Tavolga, (ed): Marine Bioacoustics. Oxford: Pergamon Press, pp. 317–336.
- Norris, K. S. (1968) The evolution of acoustic mechanisms in odontocete cetaceans. In E. T. Drake (ed): Evolution and Environment. New Haven: Yale University Press, pp. 297–324.
- Oelschläger, H. A. (1986a) Comparative morphology and evolution of the otic region in toothed whales (Cetacea, Mammalia). Am. J. Anat. 177: 353–368.
- Oelschläger, H. A. (1986b) Tympanohyal bone in toothed whales and the formation of the tympano-periotic complex (Mammalia: Cetacea). J. Morphol. 188: 157–165.
- Oelschläger, H. A. (1987) Pakicetus inachus and the origin of whales and dolphins (Mammalia: Cetacea). Gegenbaurs Morphol. Jahrb. 133: 673–685.
- Oelschläger, H. A. (1989) Early development of the olfactory and terminalis systems in baleen whales. Brain Behav. Evol. 34: 171–183.
- Oelschläger, H. A. (1990) Evolutionary morphology and acoustics in the dolphin skull. In J. A. Thomas and R. A. Kastelein (eds): Sensory Abilities of Cetaceans. Laboratory and Field Evidence. NATO ASI Series, Vol. 196. New York: Plenum Press, pp. 137–162.
- Oelschläger, H. A. (1992) Development of the olfactory and terminalis systems in whales and dolphins. In R. L. Doty and D. Müller-Schwarze (eds): Chemical Signals in Vertebrates VI. New York: Plenum Press, pp. 141–147.
- Oelschläger, H. A. and E. H., Buhl (1985a) Development and rudimentation of the peripheral olfactory system in the harbour porpoise Phocoena phocoena (Mammalia: Cetacea). J. Morphol. 184: 351–360.
- Oelschläger, H. A. and E. H., Buhl (1985b) Occurrence of an olfactory bulb in the early development of the harbour porpoise (Phocoena phocoena L.). In H. R. Duncker and G. Fleischer (eds): Functional Morphology of Vertebrates Fortschr. Zool. 30: 695–698.
- Oelschläger, H. A. and F. J., Schulmeyer (1990) Zur Morphologie und Zytologie des oberen Olivenkomplexes (OOK) beim La Plata-Delphin [abstract]. Verh. Anat. Ges. (Anat. Anz.) 83 (Suppl): 533–534.
- Oelschläger, H. A., Buhl, E. H., and J. F. Dann (1987) Development of the nervus terminalis in mammals including toothed whales and humans. In L. S. Demski and M. Schwanzel-Fukuda (eds): The Terminal Nerve (Nervus Terminalis). Ann. N.Y. Acad. Sci. 519: 447–464.
- Oelschläger, H. A., F. J., Schulmeyer, and T. Kamiya (1992) Subcortical acoustic system in the dolphin brain [abstract]. Eur. J. Neurosci. 5: 142.
- Ogawa T. and S. Arifuku (1948) On the acoustic system in the cetacean brains. Sci. Rep. Whales Res. Inst. Tokyo 2: 1–20.
- O'Rahilly, R. and F., Mäller (1994) The Embryonic Human Brain. An Atlas of Developmental Stages. New York: Wiley-Liss, Inc.
- Paxinos, G., I., Törk, L. H. Tecott, and K. L. Valentino (1991) Atlas of the Developing Rat Brain. San Diego: Academic Press.
10.1016/S0306-4522(02)00943-0 Google Scholar
- Peel, T. L. (1977) Neuroanatomical Basis for Clinical Neurology, 3rd ed., London: McGraw-Hill Book Company.
- Pilleri, G. (1964) Morphologie des Gehirnes des “Southern Right Whale,” Eubalaena australis Desmoulins 1822 (Cetacea, Mysticeti, Balaenidae). Acta Zool. 46: 245–272.
10.1111/j.1463-6395.1964.tb00721.x Google Scholar
- Pilleri, G. (1966) Morphologie des Gehirnes des Seiwals, Balaenoptera borealis LESSON (Cetacea, Mysticeti, Balaenopteridae). J. Hirnforsch. 8: 221–267.
- Pilleri, G. (1972) The cerebral anatomy of the Platanistidae (Platanista gangetica, Platanista indi, Pontoporia blainvillei, Inia geoffrensis). In G. Pilleri (ed): Investigations on Cetacea, Vol. 15. Berne, Switzerland: Brain Anatomy Institute, pp. 123–140.
- Pilleri, G. and M., Gihr (1970) The central nervous system of the mysticete and odontocete whales. In G. Pilleri (ed): Investigations on Cetacea, Vol. 2. Berne, Switzerland: Brain Anatomy Institute, pp. 89–127.
- Rawitz, B. (1908) Das Zentralnervensystem der Cetaceen. II. Die Medulla oblongata von Phocaena communis (Cuv.) Less. und Balaenoptera rostrata Fabr. Arch. Mikrosk. Anat. Entwicklungsgesch. 73: 182–260, 306–389.
- Revishchin, A. V. and L. J., Garey (1990) The thalamic projection to the sensory neocortex of the porpoise, Phocoena phocoena. J. Anat. 169: 85–102.
- Ridgway, S. H. (1986) Physiological observations on dolphin brains. In R. Schusterman, J. Thomas, and F. Wood (eds): Dolphin and Behaviour: A Comparative Approach. Hillsdale, NY: Lawrence Erlbaum Assoc., pp. 31–49.
- Ridgway, S. H. (1990) The central nervous system of the bottlenose dolphin. In S. Leatherwood and R. R. Reeves (eds): The Bottlenose Dolphin. New York: Academic Press, pp. 69–97.
10.1016/B978-0-12-440280-5.50008-1 Google Scholar
- Ridgway, S. H. and R. H., Brownson (1984) Relative brain sizes and cortical surface areas in odontocetes. Acta Zool. Fenn. 172: 149–152.
- Ridgway, S. H. and R. J., Tarpley (1996) Brain mass comparisons in Cetacea. Proc. Int. Assoc. Aquat. Anim. Med. 27: 55–57.
- Ridgway, S. H., L. S., Demski, T. H. Bullock, and M. Schwanzel-Fukuda (1987) The terminal nerve in odontocete cetaceans. In L. S. Demski and M. Schwanzel-Fukuda (eds): The Terminal Nerve (Nervus Terminalis). Ann. N.Y. Acad. Sci. 519: 202–212.
- Ries, F. A. and O. R., Langworthy (1937) A study of the surface structure of the brain of the whale (Balaenoptera physalus and Physeter catodon). J. Comp. Neurol. 68: 1–47.
- Roitblat, H. L., D. A., Helweg, and H. E. Harley (1995) Echolocation and imagery. In R. A. Kastelein, J. A. Thomas, and P. E. Nachtigall (eds): Sensory Systems of Aquatic Mammals. Woerden, The Netherlands: De Spil Publishers.
- Romeis, B. (1989) Mikroskopische Technik. 17. Aufl. ( P. Böck, ed.) München: Urban und Schwarzenberg.
- Schober, W. and K., Brauer (1974) Makromorphologie des Zentralnerven-systems 7 (1). In J. G. Helmcke, D. Starck, and H. Wermuth (eds): Handbuch der Zoologie, Vol. 8 (52). Berlin: W. de Gruyter, pp. 1–296.
- Schulmeyer, F. J. (1992) Morphologische Untersuchungen am Hirnstamm der Delphine unter besonderer Berücksichtigung des La Plata-Delphins, Pontoporia blainvillei [thesis]. Frankfurt am Main: Faculty of Human Medicine, University of Frankfurt am Main.
- Schulmeyer, F. J., H. A., Oelschläger, and J. C. Adams (1998) Specialized sound reception in dolphins–A hint for the function of the dorsal cochlear nucleus (DCN) in mammals [Historical Biology, Chur, Switzerland] (in press).
- Schwerdtfeger, W. K., H. A., Oelschläger, and H. Stephan (1984) Quantitative neuroanatomy of the brain of the La Plata dolphin, Pontoporia blainvillei. Anat. Embryol. 170: 11–19.
- Seiferle, E. (1984) Nervensystem, Sinnesorgane, Endokrine Drüsen. In R. Nickel, A. Schummer, and E. Seiferle (eds): Lehrbuch der Anatomie der Haustiere, 2nd ed., Vol. 4. Berlin: P. Parey.
- Sinclair, J. G. (1951) The terminal olfactory complex in the porpoise. Texas J. Sci. 3: 251.
- Smith, R. S. and Z. J., Koles (1970) Myelinated nerve fibers: Computed effect of myelin thickness on conduction velocity. Am. J. Physiol. 129: 1256–1259.
- Stephan, H. (1975) Allocortex. In W. v. Möllendorf and W. Bargmann (eds): Handbuch der Mikroskopischen Anatomie des Menschen, Band 4, Teil 9. Berlin: Springer-Verlag.
- Sterba, O. (1995) Staging and aging of mammalian embryos and fetuses. Acta Vet. Brno 64: 83–89.
- Sterba, O., M., Klima, and B. Schildger (1994) Proportional growth of dolphins during the prenatal period. Funct. Dev. Morphol. 4: 281–283.
- Supin, A. Y., L. M., Mukhametov, T. F. Ladygina, V. V. Popov, A. M. Mass, and I. G. Poljakova (1978) Electrophysiological Studies of the dolphin's brain [in Russian]. Moscow: Izdatel'stvo Nauka.
- Tarpley, R. J. and S. H., Ridgway (1994) Corpus callosum size in delphinid cetaceans. Brain Behav. Evol. 44: 156–165.
- Tarpley, R. J., J. B., Gelderd, S. Bauserman, and S. H. Ridgway (1994) Dolphin peripheral visual pathway in chronic unilateral ocular atrophy: Complete decussation appararent. J. Morphol. 222: 91–102.
- Verhaart, W. J. C. (1970) Comparative Anatomical Aspects of the Mammalian Brain Stem and the Cord. Assen, The Netherlands: van Gorcum and Company.
- Wanke, T. (1990) Morphogenese des Gehirns beim Schlanken Delphin Stenella attenuata (Gray, 1846) [thesis]. Frankfurt am Main: Faculty of Human Medicine, University of Frankfurt am Main.
- Watson, L. (1981) Sea Guide to Whales of the World. London: Hutchinson.
- P. L. Williams and R. Warwick, eds. (1980) Gray's Anatomy, 36th ed. Edinburgh: Churchill Livingstone.
- Wilson, R. B. (1933) The anatomy of the brain of the whale (Balaenoptea sulfurea). J. Comp. Neurol. 58: 419–480.
10.1002/cne.900580205 Google Scholar
- Worthy, G. A. J. and J. P., Hickie (1986) Relative brain size in marine mammals. Am. Naturalist 128: 445–459.
- Zvorykin, V. P. (1963) Morphological substrate of ultrasonic and locational capacities in the dolphin [English translation]. Arkh. Anat. Gistol. Embriol. 45: 647–654.