52 OSBORN. [Voe. II. 
due to the close connection between several of the cranial nerves 
at, or close to, their exit, which makes it necessary to follow 
each component bundle in continuous sections peripherad to a 
point where their further distribution can be traced macroscopi- 
cally. This I believe is possible with several of the nerves, but 
has not as yet been successfully accomplished. 
The genera studied include Amphiuma, Cryptobranchus, Nec- 
turus, Siredon, Proteus, Rana, and Szren. 
The following are some of the most important results ar- 
rived at :— 
1. The determination of the chief motor and sensory nuclei 
of the 5th to 10th pairs, which enables me in some degree to 
homologize the intra-axial elements of the Vagus and Trigemi- 
nal systems, and demonstrate the independence of the Auditory 
system and system of the motor nerves of the eyeball. 
2. The discovery of a new sensory tract and nucleus, the fas- 
ciculus communis, common to the 1oth, oth, and 7th (or 
8th) pairs. 
3. The determination of the relations of the posterior lon- 
gitudinal fasciculus (uncrossed Miillerian fibres), to the 
8th, 6th, 4th, and 3d nerve tracts, and of the nucleus of the 
latter nerve with the fibres of the posterior commissure. 
4. The passage of a portion of the descending trigemi- 
nal tract through the cerebellum and the direct connections of 
this bundle with the large mesencephalic nucleus. 
5. In the encephalon, the determination of the direct mo- 
tor tract to the prosencephalon, and of direct sensory 
tracts to the mesen- and diencephalon. 
The principal characteristics of the Amphibian brain, as 
compared with that of the Sauropsida and of the Fishes, ex- 
cluding the Dipnoi, are the following: The olfactory lobes are 
not sharply defined from the cerebral hemispheres. The corpora 
striata are not prominently developed. The cerebellum is always 
small, and is either in a primitive or degenerate condition in 
the Uvodela. The pineal eye pierces the skull, but does not 
develop further! Finally, an important distinction is that the 
! According to Spencer it is more rudimentary in the Urodela than Anura and 
in the latter forms a vesicle which subsequently degenerates. 
