80 



CETACEA 



ORDER IV 



Van Beneden ; in the Pliocene of Orciano, Italy, Monaclius ; in Antwerp, 

 Phoca, Palaeophoca, etc. Fhoca (Fig. 108) is also present in the Pleistocene 

 of Scotland, England, JSTorway and North Germany. 



Fig. lOS. 

 Plioca groenlandica Nilss. North Sea. (After Owen.) 



Order IV. CETACEA. Whales. ^ 



Naked, smooth-skinned, pisciform aquatic mammals with cylindrical body. Head 

 not differentiated from trunk. Nostrils far hack on the upper surface of the head. 

 Fore-limbs Jin-like, hind-limbs vestigial. Sacrum lacking. Caudal fluke hmisontally 

 expanded. Mammary glands in the inguinal region close to genital opening. Uterus 

 bicornis, placenta diffuse, adeciduous. 



The whales constitute an order widely distinct from other mammals owing 

 to their mode of life and their fish-like form of body. 



A thick, smooth skin envelops the entire body, and beneath this a layer 

 of fat is developed, which is a poor conductor of heat. Hairs are either entirely 

 lacking in the adult stage or are reduced in several genera to a few bristles 

 on the face. 



Cetacean bones, particularlj?- the vertebrae, are distinguishable by their 

 spongy, porous texture, and are usually impregnated with oil. The vertebral 

 epiphyses remain distinct from the centra for a considerable period, as do also 

 those of the limb bones. The anterior and posterior vertebral faces are 

 smooth and united by a thick layer of cartilage. The cervical vertebrae are 

 of the usual number, though frequently compressed, disk-like and occasionally 

 more or less fused. 



^ Abel, 0., Haiitljepauzenmg fossiler Zahnwale. Beitr. Palaont. Oster.-Ung., 1901. — Les 

 Dauphins longirostres du Bolderien. Mem. Musee Roy. Belgique, vol. i., 1900 : vol. ii., 1902. — 

 Les Odontocetes du Bolderien. Ibid. vol. iii., 1905. — Die fossilen Platanistiden des Wiener 

 Beckens. Denksehr. Akad. Wiss. Wien, vol. Ixviii., 1899. — Beneden, P. J. van, and Gervais, P., 

 Osti'Ographie des Cetaces vivants et fossiles. Paris, 1868-80. — Van Beneden, P. J., Description 

 des ossements fossiles d'Anvers. Ann. Musee d'Hist. Nat. de Belgique, vol. i. , 1877-86. — Brandt, 

 J. F., Die fossilen und subfossilen Cetaceen Europas. Mem. Acad. St. Petersb., vii. ser., vol. xx., 

 1873 ; vol. xxi., 1874. — Capellini, Giov. Mem. Accad. Sci. di Bologna, 2* ser., vol. iii., 1864 ; 4^ 

 ser. vol. iii., 1882 ; vol. iv., 1883 ; 5=^ ser., vol. i., 1891 ; 6^ ser., vol. i. 1901.— Mem. Accad. dei 

 Lineei, 1885, 4'^sev., vol. i.—Cope, E. D., The Cetacea. Amer. Naturalist, IS^O.—Eastmun, C. R. 

 Bull. Mus. Compar. Zool. Cambridge, Mass., vol. 1., 1906 ; vol. li. 1907. — Owen, R., Monograph 

 of the British fossil Cetacea from the Red Crag. Palaeont. Soc. London, 1870. 



