216 



DISSECTION OF THE DOG 



objects. Of these the most anterior is a pear-shaped grey eminence, the caudate 

 nucleus (nucleus caudatus), the narrow end of which is continued into the 

 inferior cornu. Along the medial border of the caudate nucleus runs a vascular 

 fringe, the choroid plexus (plexus chorioideus ventricuh lateralis). The 

 appearance of the plexus might lead to the assumption that it is actually 

 within the ventricle. It is, however, excluded from the cavity by a thin 



Corpus callosum 



Jfucleus caudatus ~. L _ _ 



Stria mecbullaris 



Septum -peliucidunx 



Stria terminalis 



Corpus geniculatum - 

 laterale 



■"^ Thalamus 

 ^^ Corpus pineale 

 ~~^^ Corpora quadrigetnina 



Fig. 68. — Dissection to show the floor of the lateral ventricle and the dorsal part of the mid-brain, 



cellular investment, the ependyma, continuous with that lining the whole 

 of the interior of the ventricle. Parallel to, and partially covered by, the 

 choroid plexus, is the edge of the fornix and its backward prolongation, the 

 fimbria hippocampi. The last named is a white hem appended to the greyer, 

 rounded, ridge-like eminence, the hippocampus, with the mention of which the 

 list of components of the floor is completed. 



The anterior cornu (cornu anterius) of the ventricle is, strictly speaking, 

 a mere extension of the central part beyond the level of the foramen of Monro. 



