124 PHYSIOLOGICAL SERIES. 



passage to numerous blood-vessels (not seen in the specimen) . 

 The ventricle of the right hemisphere has been opened 

 showing the thinness of the pallium, the spaciousness of the 

 cavity, and the prominence of the epistriatum. Part 

 of the right side of the cerebellum has also been cut a \vay 

 to show its remarkably thin walls and large cavity 

 continuous with the fourth ventricle. The epiphysifl i- 

 well shown. The arteries in this specimen have been 

 injected. 0. 0. 1313. Hunterian. 



D. 146. The brain of a Turtle, with the ventricles of the cere- 

 bellum, optic lobes, and cerebral hemispheres laid open. 

 The following is Mr. Hunter's description of this prepara- 

 tion : " In the first or superior ventricle is an eminence 

 which extends a little way into the olfactory nerve and 

 runs through the whole length of the ventricle. The 

 plexus choroideus is also seen in the ventricle. The ven- 

 tricle of the nates is exposed, and a white bristle is placed 

 in it, as is the ventricle of the cerebellum with a black 

 bristle lying in it. At the lower part of the ventricle is a 

 continuation of the tunica arachnoides, which shuts up or 

 makes part of the ventricle. In the angle or quadrangle 

 made by the cerebrum and nates, &c., is a duct or canal 

 like the infundibuluin leading from the upper part of the 

 skull to the last ventricle." 



In the above description the " first ventricle " is that 

 of the right cerebral hemisphere with the epist rial urn 

 ("an eminence") exposed. The "nates" (optic lobes) 

 include both nates and testes of Mammalia. The "conti- 

 nuation of the tunica arachnoides" i.s the non-vascular 

 epithelial roof of the fourth ventricle ; a small part of it can 

 be seen at the hinder margin of the cerebellum on the right. 

 The "canal "' is the l>asal part of the epiphysis. 



0. C. 1314. Hunterian. 



D. 147. The brain of a Tortoise (Te*im1t> tnf>iil,if,i). Kclative to 

 the size of the creature (the >hell measured 2,sn mm. in 

 length) the lirain i- extremely small. Its most highly 

 developed parts are in connection with the olfactory organs ; 

 the olfactory bulbs in particular being very large quite 



