THE BKAIN OF THE LEMURS. 83 



A direct comparison of this braiu with that of an Ape, and 

 especially such an Ape as Cehus, suggests the identity of this 

 furrow {g) with the sulcus centralis (Eolandi). 



If this is so — and the imperfect state of the specimen does not 

 permit me to do more than suggest the interpretation — the 

 position and direction of the sulcus are distinctly jiithecoid, and 

 in marked contrast with the Prosimian relations of the central 

 sulcus. 



Perhaps the most interesting feature in this cast is the 

 ■existence of a well-defined furrow, corresponding to the slight 

 depression labelled h (which I represented in a very doubtful 

 manner in figs. 39 and 40 of my memoir). The fragment con- 

 taining the lower end of this sulcus is unfortunatety missing. 

 Nevertheless it seems probable that this furrow represents the 

 Sylvian fissure, having a position and an extremely oblique 

 direction such as are found elsewhere only in the Apes. Behind 

 it there is a second oblique furrow {i), which must be the parallel 

 (postsylvian) sulcus, if h be regarded as the Sylvian fissure. 



The shape of the brain and the disposition of its furrows in 

 NesopitJiecus are therefore much more pithecoid than those of 

 any other Prosimian, and, in Porsyth Major's words, it " departs 

 from the Lemurids and approaches the Cebidse and Cerco- 

 pithecidse" (Proc. Royal Society, vol. Ixii. 1898). la spite of 

 these resemblances to the Apes, the conformation of the olfactory 

 region of the brain and the relations of cerebrum to cerebellum 

 point decisively to the Prosimian status of Olohilemur. 



li this interpretation of the sulci is correct (and, with the 

 knowledge of the condition presented by this specimen, I cannot 

 suggest any alternative scheme which is even plausible), the 

 brain of NesopitJiecus presents a strange mixture of decidedly 

 pithecoid and equally decided Prosimian features side by side. 

 The shape of the brain is distinctly Cercopithecoid, the plan and 

 direction of its sulci (and consequently the mode of subdivision 

 of the neopallium) diverge widely from the common Lemurid 

 arrangement, and closely resemble those of the Cebidse and 

 Cercopithecidse. On the other hand, there are the distinctly 

 Prosimian characters already mentioned , and yet Nesopithecus, 

 unlike the other connecting link, Tarsius, shows no indications 

 of being a primitive type. To attempt to explain this strangely 

 mixed association of characters on the evidence of the brain 

 would be sheer guesswork. In fact one could wish for no 



