Herrick, Brain of Certain Reptiles. 81 



radices exist ; (i) the fine layer of the fibres forming dorsal 

 remnant of the coronal fibres and (2) the basal [ventral] rem- 

 nant of the same fibres. 



[This so-called " Randfaserkranz " includes the fibres 

 which clothe the ventral and mesal surface of the hemispheres 

 immediately caudad of the olfactory peduncle.] As to the 

 ental olfactory radix, or pars olfactorii of the precommissure 

 fibres, Dr. Meyer is in doubt as to the identification (/. c. p. 81), 

 but figures them as we have done. 



Dr. Meyer describes the relations of the nucleus sphasricus 

 to the remainder of the brain base and remarks that the olfac- 

 tory radix passes through a groove of the lateral ganglion and 

 then is separated from the surface. The way in which the 

 nucleus spha^ricus is formed accounts for both facts. 



In turtles the relations are simpler, as the nucleus spJucriciis 

 can hardly be said to exist, but the occipito-basal lobe is simply 

 forced into the caudal cornu of the ventricle by a direct invagi- 

 nation the nature of which is very plain. The connection of 

 the hippocampal cortex is very close and distinct with the spur- 

 ious cortex of this region and there seems to be no reason why it 

 should not be recognized as a masked convolution. The radix 

 lateralis enters this closed fissure as described by Edinger. We 

 have verified these points in three species of Chelonia and 

 find them constant. 



The lizard Scolepoms affords an illustration of an intermedi- 

 ate condition. The "nucleus sphaericus '' is scarcely devel- 

 oped and is in obvious connection with the hippocampus. The 

 radix lateralis is somewhat submerged and enters a small blind 

 sac formed on the same plan as the corresponding organ in 

 serpents. 



In Plirynosonia our sections are very unambiguous and one 

 can easily trace the radix into the inner space of the sphaericus 

 which here lies far latero-ventrad and which is plainly an invagi- 

 nation. 



In the alligator no true "nucleus sphaericus" is formed, 

 but there is a large massive occipito-basal lobe projecting into 

 the caudal cornu of the ventricle. The transition of its super- 



