Literary Notices. xiii 



peripheral position of the spinal ganglia, and in salmon embryos they 

 are for a long time the only sensory elements provided with peripheral 

 nerves. I'hey differentiate simultaneously with the motor nerves and 

 commissural cells and disappear when the spinal ganglion cells are 

 ready to function. c. j. h. 



Natural Subdivision of the Oi>'I)ral Hemispiierc' 



Professor Elliot Smith's contribution on the Natural Subdivis- 

 ion of the Cerebral Hemisphere is based upon extensive studies in 

 comparative anatomy and yields several points of great importance to 

 the proper understanding of this part of the brain. They will be 

 especially helpful in clearing away the existing obscurity because they 

 are accompanied by exhaustive historical notes in which the various 

 conflicting usages are clearly contrasted. 



Nine distinct histological formations are recognized in the typical 

 mammalian hemisphere, as follows : 



(i) The olfactory bulb. 



(2) The olfactory peduncle. 



(3) The olfactory tubercle (tuberculum olfactorium), a peculiar 

 cortex which forms a cap upon the ventral aspect of the head of the 

 corpus striatum. 



(4) The pyriform lobe. Its anterior portion is closely applied 

 and attached to the lateral aspect of the striatum and extends forward 

 so as to pass into direct continuity with the olfactory peduncle. In its 

 caudal part the pyriform lobe becomes free from the corpus striatum, 

 and becomes a real "mantle" which extends in the caudo-mesial direc- 

 tion to become continuous with the hippocampus. 



(5) The paraterminal body, a large ganglionic mass, directly 

 continuous in front with the olfactory peduncle, extending backward to 

 the lamina terminalis and upward to fill the gap between the callosum 

 and the psalterium. 



(6) The anterior perforated space. 



(7) The hippocampal formation, sharply differentiated into (a) 

 the hippocampus [sensu stricto), and (b) the fascia dentata. 



(8) The corpus striatum. 



(9) The rest of the hemisphere, consisting of a dorsal cap, which 

 is the "neopallium." 



The grounds for the separation of the hippocampus and the "neo- 

 pallium" are discussed at some length. "Hitherto the strange irony of 



"■ Smith, G. Elliot. Notes upon the Natural Subdivision of the Cere- 

 bral Hemisphere. Jour. Anat. and Physiol., XXXV, 4, July, 1901. 



