ME. A. H. GAEEOD ON THE MANATEE. 143 



deep, in correlation with the great extent of the lobe it excavates. The walls of the 

 cerebral hemispheres are not at all thick, the lateral ventricles being capacious. 



Prof. E. R. Lankester being specially interested in the question as to the cervical 

 nerves, dissected them out in the specimen under consideration. The following are 

 his notes on the subject : — 



" Dr. Murie, in his paper on the Manatee, states that in a specimen dissected by him 

 there were eight pairs of cervical nerves, of which two pairs issued between the second 

 and third cervical vertebi-se. Hence he is led to infer that the presence of only six 

 cervical vertebrae in the Manatee's neck is to be explained by the supposition that the 

 third vertebra is suppressed, leaving the two pairs of cervical nerves before and behind 

 it, respectively third and fourth, unseparated by a vertebra. My attention was called to 

 this statement by Prof. Edouard Van Beneden of Liege, who two years since dissected 

 a Manatee at Brazil, and having especially searched for Dr. Murie's third and fourth 

 pairs of cervical nerves, had succeeded in finding but one in the position indicated. 

 Prof. Van Beneden urged me, if opportunity should occur, to examine this point care- 

 fully in the Manatee then living in Regent's Park. I was kindly allowed to make this 

 investigation by my friend Prof. Garrod ; and I have to state that the following result 

 was obtained by making first of all a dissection of the external course of the cervical 

 nerves, and subsequently removing the skull and first three cervical vertebrae one by 

 one, so as to trace the nerves to their origin in the medulla. A single pair of nerves 

 issues between the occiput and atlas, a single pair between the atlas and axis, a single 

 pair between the axis and third cervical vertebra, a single pair between the third and 

 fourth cervical, and a similar arrangement obtains for the fourth and fifth, fifth and 

 sixth, sixth and first dorsal. The piece of the spinal cord, with the pair of nerves 

 attached to it, which issues between the axis and third cervical vertebra (hence the third 

 pair of cervical nerves) was removed by Prof Garrod and preserved in spirit. The 

 third pair of cervical nerves is considerably larger near its origin than is either the first 

 or second nerve ; but the most marked increase of bulk is observed in the fourth, which 

 issues between the third and fourth cervical vertebrae. There was no trace in the 

 specimen dissected of any additional nerve, or of any structure which could be taken for 

 such a nerve, in the interspace between the second and third cervical vertebrae. The 

 third cervical nerve is connected by a slip to the fourth, and furnishes through this 

 slip the highest origin for the phrenic nerve. 



" Dr. Murie does not expressly state that he followed his supposed two pairs of 

 cervical nerves issuing between the second and third vertebrae to their origin in the 

 medulla; and from his drawing one is justified in supposing that he drew an infer- 

 ence as to the existence of these two pairs of nerves from the position of two nerve- 

 trunks, which it is possible he would have found united to form a single trunk if he 

 had pursued them to their origin. 



" The fact which I am anxious to put on record is, that in two Manatees dissected 



