MOEPHOLOGT OF THE BRAIN IN THE MAMMALIA. 



339 



except that no trace of a ridge corresponding to tlie postsylvian sulcus was present. 

 There is neither a coronal nor a postlateral sulcus. 



In a skull of Lepidolemiir leucopus in the British Museum there is no trace of eitlier 

 the orbital, coronal, or postsylvian sulci, or of the furrows e and /' in Lemur. 



So far as I am aware, all that is known of the brain itself in this genus is represented 

 by a series of not altogether satisfactory drawings (without any description of any kind, 

 except the legend " brain of Lepidolemur ruficaudatus ") in Milne-Edwardss work *. 



From an examination of the profile (fig. 1 b), one iniglit imagine that typical coronal 

 and lateral sulci of the Lemurid type were present ; but the appearance presented l)y 

 the sketch of the dorsal surface (fig. 1) is so different that it is difficult to believe that it 

 represents the same brain. As I had inferred from the examination of two of the three 

 skulls, there is no postsylvian sulcus. 



These drawings unfortunately give us little information of any value. 



So far as I am able to judge from the crania which I have examined, the brain must 

 present many features resembling those of the Indrisiiise and others (of less importance) 

 like those of the Lorisin;B (especially Ferodicticus) and Galagime. 



F.g.9. 



y. sp 



Fig. 9. — Nycticehus tard'njradus. Dorsul aspect of a cranial cast. Nat. size. 



Fig. 10. — Si/ctictbus tardiijradiuH. Left aspect of a brain. 2^at. size. 



Fig. \\.—yijctictbus tardigradus. Lateral aspect of the left cerebral hemisphere of another b 



rain. Nat. size. 



The Brain ix the Lorisin.e, 



It is convenient to consider Nycticehus first. The brain in this genus is not only 

 smaller than that of Lemur, but also presents some noteworthy difi'erences in shape. 



The cerebral hemispheres of the only fresh specimen of yycticebus tardigradus m hich 

 I have seen are 34. mm. long, 28 mm. wide, 23 mm. high. 



• Uistoire de Madagascar,' (2) tome vi. 43- fasc. 1S97, pi. 273. figs. 1, 1 a, 1 5, 1 c, and 1 d. 



