CHAP. IV] THE GENERAL ANATOMY OF THE LEMUROIDEA 



85 



H. Nervous System : the Brain (Figs. 44, 45). Some of 

 the cerebral characters of the Lemuroidea have been enumerated 

 already (cf. p. 46). They were adduced in support of the case for 

 the inclusion of the Lemurs in the Order Primates. Here it is 

 necessary to add further details. But in setting out these features, 

 and in any attempt to appraise their value in evidence, certain 

 preliminary considerations must be borne in mind. 



3.CENT 



•s S.SUPRASYL. 



S.DIAG. 



S.COROK 

 S.QRB. N \ 



POST.SYL 



B.OLF. 



Fig. 44. Brain of Lemur mongoz. Lateral aspect. (Mus. Anat. Cant.) 



(i) Some features of the Lemurine brain are undoubtedly 

 primitive as compared with the corresponding characters in the 

 animals grouped together as the Sub-order Anthropoidea. Of 

 such characters, the most impressive example is probably that 

 afforded by the conspicuous olfactory bulb and tract. 



S.PARACALC. 



S.INTERCAL 



s.olf: 



Fig. 45. Brain of Lemur mongoz. 



• FISS.RK1N 

 Mesial aspect. 



(Mus. Anat. Cant. 



(ii) Other characters, though seemingly primitive, may never- 

 theless indicate a reversion or a degeneration : the relatively feeble 

 development of cortical folding in the " true " Lemurs may be 

 cited as an example of characters determined by such processes. 



