338 PEOF. G. ELLIOT SMITH ON THE 



being 35 mm. long and 2S mm. broad : the cori-esponding measurements •♦in the species 

 simits were 40 mm. and 31 mm. respectively. The brain of Sajjalemur therefore is 

 considerably smaller than the average size in Lemur. 



In the braia of Hapalonur simus (Proc. Zool. Soc. 1901, p. 127, text-fig. 24) the upper 

 end of the suprasylvian sulcus is bifid; but it is not fused to a long sulcus d, as is the 

 ease in Beddard's first specimen of the genus, griseus {ibid. p. 128, text-fig. 25). There 

 is a typical coronal sulcus in both species, bent in exactly the same jnanner as so often 

 liappeus in the genus Lemur. Lateral, orbital, parallel, and even diagonal sulci and the 

 I'urrow _/ occur exactly as in the genus Lemur. 



It is clear that the brain of Hapalemur is, to all intents, identical with that of Lemur ; 

 and the features which Beddard thinks may possilily amount to specific characters can 

 be nothing else than variations such as we find in almost every species of Lemur. 



H. O. Forbes states* that "the brain [in the genus Hajxtlemnr] is narrower^ and 

 shallower than that of the genus Lemur, and presents no specially close resemblance to 

 the same organ in the Lndrisirue or the Lorisiiice." With the latter part of this quotation 

 I quite agree ; and if the former part is also true, it indicates, in comparison with 

 Lemur's brain, a slightly nearer approach to the pithecoid type. 



The Cerebral Hemisphere in the Gends Lepidolemur. 



The olfactory bulb appears to project beyond the hemisphere as it does in the Lorisinag, 

 the Galaginiie, and in Tarsius. 



The pattern of sulci which a study of the cranial ridges in a series of skulls has 

 shown to exist in Lepidolemur differs in many respects from the arrangement which 

 is common to the genera Lemur and Kapalemur. 



Fig. 8. 

 see. si. 



Lepidolemur in usteliit.ua. 

 Lateral aspect of the cranial cast of the left cerebral hemisphere. Xat. si/.e. 



In a skull of Lepidolemur musteliuus iu the British Museum there are ty^jical simple 

 linear Sylvian, lateral, orbital, and a very shallow postlateral sulcus, and another sulcus 

 apparently representing the conjoint elements e and /, such as often hap2)ens in Pro- 

 piihecus and Fcrodicticus. This specimen also closely resembles that of one of the 

 specimens of Avahis which I examined, the protruding olfactory bulbs coustitutino- a 

 small and relatively vmimjjortant difference. 



A second skull of the same species exhibited a pattern of sulci exactly similar to this, 



* '• Monkeys," vol. i. (Allen's Naturalist 'a Library, 1893), p, SI. 



