NATURAL SCIENCES OF PHILADELPHIA. 455 



is absent in the Manatee, as I found no trace of it at its usual 

 origin. If such is the case, I should regard Murie's 6th nerve as 

 the 7th, and his 8th as the pars intermedia; his 7th would then 

 be 8th. I was unable to trace out these nerves, being anxious to 

 take out the brain as soon as possible. The glossopharyngeal, 

 pneumogastric, and spinal accessory were readily recognized. 

 The hypoglossal came off internally and above the position repre- 

 sented by Dr. Murie in Fig. 33, Plate 25. On making sections I 

 found the corpus callosum extending but little posteriorly; the 

 fornix was well developed, particularly the posterior part. The 

 lateral ventricle is long and deep, the anterior and middle corner 

 very apparent, while there is a beginning of a posterior one. The 

 corpus striatum is well developed, as also the thalamus opticus. 

 There is a delicate taenia semicircularis. The choroid plexus is 

 rich. The hippocampus major is present, but not as thick rela- 

 tively as the hippocampus minor. There is apparently a corpus 

 fimbriatum. The velum interpositum was well injected, and on 

 removal revealed the pineal gland with its peduncle. The 3d ven- 

 tricle is deep. The corpora quadrigemina are large, but are really 

 bigeminal bodies, there being only a slight indication of division 

 into nates and testes. The processui e cerebello ad testes are well 

 seen, supporting a firm valve of Vieussens, under which a bristle 

 readily passed from the 4th to the 3d. ventricle. The cerebellum is 

 higher, as 1 have already mentioned, and broader than that repre-. 

 sented by Dr. Murie, almost as broad as the cerebrum, its breadth 

 being 3 inches. I noticed in its vermiform process, the floculus and 

 the amygdaloid bodies. The pons and medulla are both flat, but 

 the olivary and restiform bodies are, however, distinguishable. 

 The brain weisiied 7 ounces 14 drachms av. Di reference to the 

 distribution of the cranial nerves I have nothing new to offer. As 

 regards the cervical plexus, I found its disposition to be the 

 same as described by Dr. Murie, noticing the interesting peculi- 

 arity of the 3d and 4th cervical nerves, emerging together from 

 between two contiguous vertebrae, viz., the 2d and 4th. The 

 missing vertebra I regard, with Dr. Murie, as being the 3d. For 

 since the 8th cervical nerve, contributing to form the brachial 

 plexus, escapes from between the 1st dorsal and a contiguous 

 vertebra, which must, therefore, be the 7th cervical, and as the 

 7th, 6th, and 5th cervical nerves emerge from between contigu- 

 ous vertebrae, which must for the same reason be the 7th, 6th, and 



