Page 144. 
310 ON THE MANATEE, 
Hence he is led to infer that the presence of only six cervical verte- 
bree 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 Professor 
Edouard Van Beneden, of Liége, who two years since dissected a 
Manatee in 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. Professor Van Beneden urged me, 
if opportunity should occur, to examine this point carefully in the 
Manatee then living in Regent’s Park. Iwas kindly allowed to make 
this investigation by my friend Professor 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 remov- 
ing 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 arrange- 
ment 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 the third cervical vertebra 
(hence the third pair of cervical nerves) was removed by Professor . 
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 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 inter- 
space 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 inference 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 since the publication of Dr. Murie’s statement as 
to these cervical nerves, careful search was made with the view of 
confirming his statement, and the condition described by him was not 
found to obtain ; but the usual and normal arrangement of a single 
