104 CETACEA. 



There is a vast number of glands about the neck and heart, espe- 

 cially along the attachment of the pericardium to the diaphragm ; 

 whether lymphatic or not, I am not certain. The veins of this animal 

 are very large and many. There are a great many plexuses of the 

 arteries among the muscles of the neck and head, running in a con- 

 torted manner. The intercostal arteries arise from the aorta by three 

 trunks, and are subdivided into three intercostals. There is a vast 

 plexus of the arteries that lie between the pleura and ribs, just at the 

 angle of the rib all along the spine. The eyes are smaller in proportion 

 to the size of the body than in any other fish ; and more so than those 

 of the land animals of their class 1 . The coats of the eye are very 

 much like the human, or most land animals of then' class ; only that 

 the sclerotic coat is much thicker, especially the nearer the optic nerve. 

 The crystalline humour is nearly round, if not quite. [The right eye ; 

 the outer or rather the posterior part cut off. The gland at the inner 

 or anterior angle ; no puncta lacrymaha, nor sac 2 .] 



The external ear is only a small flattened canal leading from its 

 opening in the skin (which only appears to be a little aslant in the 

 skin) to the organ of hearing 3 . 



The brain of the porpoise 4 is, in its parts, similar to the human and 

 animals of this [mammalian] class. In general it is much shorter, broader, 

 and flatter than in any other animal. It consists of cortical and medul- 

 lary substance ; of cerebrum, cerebellum, and medulla oblongata. The 

 cerebrum consists of two hemispheres : the convolutions are irregular. 

 There are two lateral ventricles, with plexus choroides 5 , and corpora 

 striata ; also thalami optici, third ventricle, and infiuidibulum. I could 

 not observe the ' nates ' or ' testes,' nor the pineal gland, those parts 

 being very putrid. The cerebellum is convoluted as in the human. 

 There was a fourth ventricle, and the arbor vitas. The medulla 

 oblongata is flat ; the corpus annulare was not so perceptible as in the 

 human. There were no olfactory. nerves. The optic nerves unite and 

 make a very sharp angle at their union. 



The medulla spinalis 6 is in most respects similar to the human. The 

 nerves arise in pairs, and each nerve arises by two portions ; one from 

 the upper or posterior surface, the other from the lower or anterior 

 surface. The dura mater is connected to the nerves near their origins 

 all the way down ; therefore the cauda equina is on the outside of the 

 dura mater, not within it, as in the human subject. They pass out 



1 [Meaning the amphibious, as the seal-tribe.] 



" [Hunt. Preps. Nos. 1(377, 1678, 1GS8, 1773 — 1775: this last is the preparation 

 above defined.] 3 [lb. Nos. 1582, 1587—1592.] 



* [lb. Nos. 1332, 1333.] 3 [lb. No. 1334.] 6 [lb. Nos. 1359, 1360.] 



