448 PHYSIOLOGICAL SERIES. 



.interior commissure, lamina terminalis, and the large optic 

 chiasuia. The anterior commissure is slightly larger than 

 in the human hrain and the optic tracts are considera bly 

 greater. 



It is of interest to note the presence o a large ventricle 

 of Verga under the posterior part of the corpus callosum 

 an anomaly occasionally found in the human hrain. 



The other structures exposed in the mesial section closely 

 resemhle the corresponding features of the human hrain. 

 They are here shown exceptionally clearly. Note especially 

 the foramen of Monro, the soft commissure, the ganglion 

 hubennlse, the posterior commissure, the smooth lateral 

 wall of the third ventricle, the optic recess, the remains of 

 the embryonic optic diverticulum just ahove the optic 

 chiasma, the aqueduct of Sylvius and the fourth ventricle. 

 [The description of all these structures found in text-hooks 

 of Human Anatomy applies equally here.] 



The cerebellum has now assumed a close likeness to the 

 human organ. The floccular lobe, however, is still larger 

 than it is in most human brains, although it is subject to 

 extreme variation in Man as in the Anthropoid Apes. The 

 floccular lobe, which is best seen on the left side, is com- 

 posed of two distinct lobules each attached by its own 

 stalk. Of these, the mesial is much the larger and plumper 

 of the two and is composed of three separate groups of 

 folia (three or four in each group), the separate stalks 

 of which unite into a common peduncle. The lateral 

 lobule is much smaller and is almost hidden by the mesial 

 lobule. Two or three of its folia may, however, be seen 

 emerging in the great horizontal fissure external to the 

 ine-ial lobule. 



There can be no doubt that the lateral lobule represent* 

 the flocculi secundarii of Man, and these may correspond 

 to the paraflocculus (although much fuller developmental 

 evidence than Stroud [Journ. Comp. Neur. 1895] adduces 

 is necessary to prove the identity). 



In appearance the other par!.- of the brain exposed 

 in these specimens closely resemble the corresponding 

 region- in the human brain. The olivary body i> now in 

 contact \\ith the lower border of the pon.-. To the naked 



