THE LATERAL VENTRICLE. IIQ 



is directed forward. It is seen in the anterior horn of the lateral 

 ventricle. From the head the nucleus tapers as it proceeds back- 

 ward through the central part of the ventricle. Its tail (cauda) 

 turns downward in the roof of the inferior horn, and ends in a 

 considerable mass of gray substance called the nucleus amygdala, 

 which appears to be an ingrowth of cortex from the region of the 

 uncus hippocampi (Fig. 32). The caudate nucleus is covered 

 on its ventricular surface by ependyma. The opposite surface, 

 resting against the fibers of the internal capsule, is irregular and 

 serrated. 



The stria terminalis (taenia semicircularis, Figs. 30 and 36) 

 lies just medial to the nucleus caudatus. It is a band of white 

 fibers traversing the floor of the central part of the ventricle and 

 the roof of its inferior horn, but covered by the terminal vein 

 and by the ependyma. It may be said to rise from the nucleus 

 amygdalae. Ascending to the ventricle, it passes forward between 

 the caudate nucleus and the thalamus to the interventricular 

 foramen, where it divides into two bundles. One of them accom- 

 panies the columna of the fornix for a little way. The other, 

 passing over the anterior commissure, descends in front of it ; and, 

 according to Kolliker, both bundles end in the anterior perforated 

 substance (Cunningham). The thin medial border of the sub- 

 stance covering the vena terminalis, which is attached to the 

 thalamus, is called the lamina affixa; it is present only in the body 

 of the ventricle. The lamina affixa is joined by a single layer of 

 epithelium, the lamina chorioidea epithdialis, to the lateral border 

 of the fornix. This lamina invests the chorioid plexus of the 

 lateral ventricle. If the chorioid epithelium be torn away, the 

 edge which remains on the stria terminalis is called the t&nia 

 terminalis. 



Thalamus (Figs. 30, 31, 36 and 40). A fusiform part of this 

 ganglion of the inter-brain is visible in the floor of the lateral 

 ventricle, between the stria terminalis and the chorioid plexus. 

 It extends throughout the central part of the ventricle from the 

 interventricular foramen to the inferior horn. A transparent 

 layer of epithelium, the lamina chorioidea epithelialis, extending 

 from the fornix to the stria terminalis and representing the hemi- 



