MR. A. H. GARROD ON THE MANATEE, 1438 
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 vertebre. Hence he is led to infer that the presence of only six 
cervical vertebra 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 bya vertebra. My attention was called to 
this statement by Prof. Edouard Van Beneden of Liége, 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 vertebree 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 cervica] vertebre. ‘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 vertebre. ‘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 vertebre 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 
