MOEPHOLOGY OF THE BRAIN IN THE MAMMALIA. 377 



if there be any q\ialitativc diffcveace in Ihe nature of the occipital prolongation of the 

 hemisphere in Lemurs and Apes. For the extent of this region of the hemisphere, or, 

 rather, its relation to the cerebellum, is commonly supposed to be a feature of the 

 iitmost importance as an index of cerebral development, even by writers who have 

 devoted much labour to the study of this part of the brain. 



This will lead not unnaturally to the enquiry as to whether the oxlcarine sulcus is 

 found in any mammals other than ihe Primates. 



The most conflicting statements are found in the literature (quoted earlier in the 

 notes) regarding the posterior cornu of the lateral ventricle. 



Burmeister (1846) described an extensive diverticulum of the ventricle in Tarsim, 

 and about the same time Vrolik denied its presence in }\ijcticebu,s \Slenops\. Both ol' 

 these statements are true. 



In 18C2 riower thought that he had found a postx'rior cornu and calcar in Lemur 

 /ulcus {^nigrifrovs] and also in a Galago of unknown species ; but while his monograph 

 was being revised in proof he became sceptical and added in a footnote: "A further 

 examination of this specimen [a brain of dalago in tlie Museum of tiie Charing Cross 

 Hospital], and of the brains of some allied genera, leads me to doubt whether the above 

 described ' cavity' in the posterior lobe existed before dissection, the length of time that 

 it had been in spirit having greatly facilitated this process. If it did not, it will justify 

 the statement of the absence of the hippocampus minor by anatomists who have looked 

 at this structure only in its relation to the postei*ior cornu, but at the same time will 

 afford a further illustration of what I have endeavoured to show .... viz. : — that the 

 part of the brain to which this term [calcar] has been applied can exist indej)endently 

 of the ventricular cavity " (Phil. Trans. 1S02, p. 198, footnote). I have quoted 

 this very interesting and luminous note in full, not only by reason of its important 

 bearing upon tiie question at issue, but also to express surpri.se that its author shoukl have 

 suddenly stopped on the way to the full interpretation of tlie morphology of the calcar 

 and calcarine sulcus, and have categorically denied its existence in the Cat's bi-ain, after 

 thus removing all the obstacles to such an obvious inference as to the identity of the 

 so-called " spleuial '' sulcus in the Cat and the Prosimian calcarine. In the same year 

 he wrote a second memoir [which, however, was not published until 1800 (Trans. 

 Zool. Soc. vol. V.)], in which he makes the statement that it is imjiossible to determice 

 whether or not the posterior cornu exists in }\ijcticehus tardigradus [Stenops Javanicus] 

 (p. 100). 



In the memoir on rhe brain of Chiromys, which was published in the same year 

 (Trans. Zool. Soc. vol. v.), Owen seems to represent a small posterior cornu (in fig. 5). 

 This fact is all the more significant if it is intentional, as the author was engaged at the 

 time his memoir was Avritten in a heated controversy, in which he maintained that the 

 posterior cornu and the calcar were human characteristics. 



In Milne-Edwards's contribution to the History of Madagascar ((2) tome A-i. 1876, 

 p. 206) the author refers to Flower s demonstration of tiie existence of a calcar in Lemur 

 and Galago (quoting Piiil. Trans. 1862, p. 197), and states that he has confirmed this in 

 the case of the forms studied by Flower, but denies its (calcar's) existence in Indria, 



