366 ANATOMY OF THE RABBIT 



(c) The floor of the lateral ventricle is formed by two somewhat 

 oblique, convex ridges. One of these, posterior and medial 

 in position, is the hippocampus, a part of the pallium which 

 has become folded inwards to form the ridge observed pro- 

 jecting into the ventricle. The other, anterior and lateral 

 in position, has a smaller ventricular exposure but is a 

 greatly thickened solid mass of nervous matter, the corpus 

 striatum (Fig. 117). Between the two ridges, the pig- 

 mented vascular tissue of the chorioid plexus of the lateral 

 ventricle may be made out. The hippocampus is a region 

 where olfactory stimuli coming from the pyriform lobe and 

 from more medial secondary olfactory areas are correlated 

 with others, chiefly of visceral origin. The corpus striatum 

 is related to the control of bodily movements. 



(d) On the medial wall, the thickened posterior portion forms 

 the body of the fornix, immediately in front of which is 

 the thinner portion of the wall, described above as the 

 septum pellucidum. 



9. The passage of the olfactory nerves to the ethmoturbinal sur- 

 faces may be traced by removing the nasal bones and working 

 downward toward the cribriform plate, or the remaining portion 

 of the skull containing the nasal region still intact may be 

 divided vertically for a more extended examination of the nasal 

 fossae. The features to be observed are largely those described 

 in connection with the skeleton (pp. 178, 190). 



