336 THE ANATOMY OF VERTEBRATED ANIMALS. 



sent the iscliia. They are elongated, convex upward and con- 

 cave downward, and are connected with the vertebral column 

 only by fibrous tissue. In some few Cetacea {J^aloenoidea) 

 ossicles, which lie on the outer side of the pelvic bone, appear 

 to represent the femur, but no further indication of a hind- 

 limb has been discovered. 



In most of the Cetacea^ the muscles which, in other Marin- 

 malia^ move the antibrachium and the nianus, are absent, 

 those which move the humerus upon the shoulder-blade being, 

 alone, represented. 



In no recent Cetacean have the teeth any vertical suc- 

 cessors, nor more than a single root. The alveoli are often 

 incompletely separated from one another. The number of the 

 teeth varies very greatly, but they are almost always nearly 

 uniform in character. There appear to be no salivary glands. 

 The stomach is" complicated, being divided into, at fewest, 

 three chambers, of which the first is a kind of paunch lined by 

 a thick ej^ithelium, while the second and the third are more 

 elono'ated, the last stomach beino- that in which dio-estion 

 takes place. 



The arteries and veins form great plexuses, or retia mi- 

 rahilia, and these are especially conspicuous in the cavity of 

 the thorax, upon each side of the vertebral column, and in the 

 intercostal spaces. 



The soft palate is remarkably long and muscular. The 

 epiglottis and the arytenoid cartilages are more or less pro- 

 duced, so as to give the glottis the shape of a funnel, the apex 

 of which is embraced by the soft palate, in such a manner as 

 to form a continuous air-passage from the posterior nares to 

 the larynx, on each side of whicb the food passes. The very 

 short trachea, before it divides into the bronchi, gives ofi" the 

 so-called " third bronchus " to the right lung, as in the Bears, 

 Walruses, and Ruminants. 



The kidneys are deeply subdivided into lobules. In the 

 male the testes always remain in the abdomen, and there are 

 no vesiculas seminales. The penis is devoid of a bone. The 

 uterus of the female is deeply divided into two horns, and the 

 villi of the foetus are scattered over its chorion, as in other 

 mammals with a diffuse placentation. 



The Cetacea are divisible into three groups : the JjcilcB- 

 noidea, the Delphinoidea^ and the PhocodoiitlaJ^ 



* For further information respecting the characters of the recent Cetacea^ I 

 refer the reader to Prof. Flower-s's v-eiy valuable memoir " On the Osteology 

 of Inia and Fontryporia^'' published in the "Transactions of the Zoological 

 Society for 1867." 



