NERVOUS SYSTEM. VERTEBRATA. 265 



hippocampus. The corpora quadrigemina are fully ex- 

 posed,and the narrow, elongated, fourth ventricle opened up. 

 Upon the dorsal aspect of the spinal cord note the ex- 

 ceedingly delicate columns of Goll alongside the mesial 

 septum swelling out slightly at the calamus scriptorius to 

 form the nuclei graciles. The columns of Burdach are 

 much broader and swell out into the nuclei cuneati. 



O.C. 1325 K a. 



D. 327. The brain of a Dog (Canis familiaris). 



In the left hemisphere the coronal is completely separate 

 from the lateral sulcus. But the latter is connected with a 

 deep and extensive ansate which passes into a minor ansate 

 sulcus opening into the suprasylvian. The ectolateral 

 sulcus also joins the minor ansate. 



On the right side there is no communication of the 

 minor ansate with either the lateral or ectolateral sulci. 



The crucial sulcus presents the unusual phenomenon for 

 a Cynoid of being bifid. 



In this specimen all the cranial nerves except the 

 trochlear (iv) are well shown in the usual positions. 



O.C. 1325 K. 



Langley, Journ. of Physiology, vol. iv. p. 248. 



D. 328. The head of a Dog ( Canis familiaris) cut in longitudinal 

 section to show the relation of the brain to the skull. 



Note especially the large olfactory bulb separated from 

 the nasal fossa by the thin cribriform plate. 0. C. 1325 K b. 



D. 329. Two casts of the cranial cavity of a Dog (Canis fami- 

 liaris). These casts show the true shape o the olfactory 

 bulbs and their relations to the hemispheres. 



D. 330. The brain of a South- American Fox -Wolf (Canis azarce), 



( ? juv.). 



On the left hemisphere there appears to be a relatively 

 extensive ectolateral sulcus, whereas on the right side this 

 sulcus is seen to be very short, and the separate lower 

 snlcus which represents the greater part of the apparent 

 ectolateral of the other hemisphere is clearly the postlateral 

 sulcus. O.C. 1325 L*. 



