694 DR. E. CRISP ON THE HIPPOPOTAMUS. [JuilC 27, 



Kidney and Renal Body. — The kidney in the Elephant and Rhi- 

 noceros, like that of the Hippopotamus, is generally lobate ; whilst 

 in the Pigs, Tapirs, Peccaries, Hyrax, and members of the equine 

 family it is entire. The renal body in the Hippopotamus is placed 

 further from the kidney than in the other pachyderms, in which it 

 is generally in contact with this organ. In the two Elephants that 

 I examined (Proceedings, 185.5, p. 18/) the kidneys of the female 

 were lobated, whilst those of the male were entire. 



Organs of Generation. — All the animals belonging to this family 

 have the generative organs largely developed. In the Pigs the tes- 

 ticles and seminal vesicles are very large. The penis is also large in 

 all, that of the Tapir proportionately larger, I believe, than in any 

 other of the class. The age of this animal precludes a comparative 

 estimate as regards size ; and the accidental loss of the organs, as I 

 have said before, prevented my making an accurate dissection. 



The tongue, like that of the Wart-Hog {Phacochcerus aethiopicus) 

 is thin and broad at its anterior part. The white papillae I have 

 mentioned are seen in all the Pigs and in the Tapirs ; but the form 

 of the basal villi diflPers from that of the other pachyderms. 



Larynx and Trachea. — One important difference in the larynx of 

 the Hippo])otamus is the pyramidal form of its summit and the great 

 development of the laryngeal muscles. The os hyoides consists of 

 the usual number of bones. The trachea is composed, as I have 

 stated, of twenty-three rings, rather widely separated at the posterior 

 part, as is seen in the dried larynx before the Society. The number 

 of rings in the Horse and Zebra varies from 4.5 to 52 ; in the Ele- 

 phant — , Rhinoceros (Owen; 30, Common Hog 28, Wart-Hog 28, 

 Peccaries 33, Tapir (American) 32, and Hyrax 30. 



So that, judging from this young animal, the Hippopotamus has 



the smallest number of tracheal rings of any of the pachyderm family. 



The thyroid glands were perfectly distinct ; whereas in some of 



the pachydermata, as in the Horse, there is a connecting isthmus as 



in Man. 



The lungs consist chiefly of two lobes, as in the Seal, Dolphin, 

 and Porpoise; in the Elephant , Rhinoceros (Owen) 5, Tapirs G, 

 Hogs 6, Peccaries 7, Hyrax 0, and Horse 5. In some of these a very 

 small lobe exists in addition. 



The lobular divisions I have before described, I believe, are pecu- 

 liar to the lungs of this quadruped, and are not found in the other 

 pachyderms. In the above description both lobes are spoken of. 



The heart, with the exception of that of the Elephant, is of a less 

 rounded form in the other members of this group. The opening of 

 the two superior cavee into the right auricle only exists in the Ele- 

 phant. There are also some important differences in the appendages 

 to the muscular walls of the heart ; but want of space prevents me 

 from alluding to them on the present occasion. The most interesting 

 point in connexion with the heart is its bifid character in the newly 

 born animal, as mentioned by Gratiolet in the paper before cited ; 

 he says " C'est peut-etre un iudice de cette division du cceur qui 

 a ete' signale dans la Rhytino, Ics Duyonys, et les Lamnntins.'''' 



