NERVOUS SYSTEM. VERTEBRATA. 115 



A small epiphysis lies between the hinder ends of the 

 hemispheres. The infundibulum is prominent and gives 

 attachment to a large spherical hypophysis. 0. C. 1318 A. 



D, 132. The brain of an Indian Python (Python molurus) in 

 sagittal section seen from the left. The dor so- ventral 

 flattening of the brain is well seen. The right olfactory 

 bulb and peduncle and the cerebral hemisphere have been 

 sagittally divided to show their cavities. That of the 

 olfactory bulb is capacious and is connected with the lateral 

 ventricle by an extremely delicate lumen in the ventral 

 part of the peduncle. From the outer wall of the hemisphere 

 a pair of lineally arranged eminences (corpus striatum) 

 project into the ventricle. Beneath them can be seen the 

 cut surface of the lower part of the striatum. The mesial 

 wall of the hemisphere has been mounted on the right 

 side to show the paraterminal body a longitudinal ridge- 

 like thickening of the wall that fits into a depression 

 along the lower border of the striatum. 



The flattened tectum opticum is separated into corpora 

 quadrigemina by a longitudinal fissure (shown in the pre- 

 vious specimen) and by a shallower transverse groove, 

 visible in this specimen as an indentation upon the cut 

 edge between the posterior two thirds. The posterior 

 eminences are formed by a pair of nuclei that contribute 

 fibres to the fillet. In the Snakes the large trigeminal 

 roof -nucleus situated along the mesial area of the tectum 

 beneath the commissural layer is seen to advantage. The 

 openings from the aqueduct of Sylvius into the lateral 

 optic ventricles are small and situated far forward. The 

 cerebellum, although small, is relatively thick. The rhom- 

 boid fossa is covered by a delicate membranous roof, the 

 anterior part only of which, as in the Turtles, is pleated 

 and vascular. 



The hypophysis is mounted on the left, below the in- 

 fundibulum ; it shows well the two parts of which it is 

 composed. 



The Snake from which this specimen was obtained 

 measured 15 feet in length. 



Rabl-Ruckhard, Zeits. wiss. Zool., Bd. Iviii. 1894, p. 694. 



12 



