380 



is convex, both from above downwards, and in the antero-posterior 

 direction, so that the axis of the cavity that contains it, though 

 directed generally backwards, has first an outward inclination, and 

 finally turns somewhat inwards. The anterior or broad end of the 

 eminence is concave, being adapted to the curved posterior margin 

 of the hippocampus major, from which it is separated by a deep 

 groove. The length of the hippocampus minor is ? of an inch, 

 its breadth at the base almost as much. The outer wall of the 

 ventricle has a distinct projection into the angle between the hippo- 

 campi, nearly corresponding with the * eminentia collaterals ' of the 

 human brain. On comparing the posterior lobe and hippocampus 

 minor in Galago with the same parts in the true apes (e. g. Cerco- 

 pithecus), it is seen that though the anterior part is proportionally 

 as broad, the length is considerably diminished ; the portion that is 

 wanting being equivalent to that part which, in the apes, covers the 

 posterior third of the cerebellum, and projects beyond it." 



As none of the authors who have written upon the brains of the 

 Lemuridae describe a hippocampus minor, as Vrolik expressly 

 states that it is absent in Stenops, and as Burmeister alone assigns 

 a posterior cornu to the ventricle (in Tarsius), it seemed desirable, 

 after the results of the observation of these parts in Galago, to re- 

 examine the brain of some other members of the family. Two speci- 

 mens in spirit of Loris (Stenops) Bengalensis, placed at the author's 

 disposal for this purpose by Dr. Grant, afforded distinct evidence of 

 the existence of a well-developed posterior cornu and hippocampus 

 minor, though unfortunately in neither instance were the brains in 

 sufficiently good preservation to allow of a satisfactory description 

 or figure of the parts being made. 



Galago and Stenops being generally considered as not very elevated 

 forms in the Lemurine family, we can have but little doubt as to 

 the presence of the posterior cornu and hippocampus minor through- 

 out the different members of the group, and hence a most important 

 character is supplied for determining the affinities of these interesting 

 animals. It indicates as decisively their position among the Qua- 

 drumana, as it separates them completely from the Insectivora, in 

 which order some naturalists have placed them. 



Many links are still wanting in the chain of evidence required to 

 determine the true history and classificatory value of the posterior 



