82 PKOF. G. ELLIOT SMITH ON" 



since the information which would be conveyed by the small 

 missing fragments (fig. A, * and /") would have enabled us to 

 decide with absolute certainty all the doubtful issues raised in 

 the previous discussion. 



In the smaller fragment, the coronal and diagonal sulci are 

 exceptionally deep and sharply defined, so that their identity is 

 placed beyond all doubt. In shape and position they closely 

 resemble the furrows h and e (Mem. fig. 40) in the type- 

 specimen. In the other specimen (fig. A) the coronal sulcus is 

 broken up on both sides into a small anterior (? prorean) frag- 

 ment (&') and a long posterior sagittal furrow (5). The gyrus- 

 included between the coronal sulcus and the interhemispheral 

 cleft is 7 mm. broad in front and 11 mm. broad at its posterior 

 extremity. The relative smallness of this gyrus is in marked 

 contrast with its size in the Apes and even in most Lemurs. 

 Thus the corresponding measurements in a specimen of Cerco- 

 fithecus patas are 6 mm. and 20 mm. respectively, and in a 

 Lemur macaco 4 mm. and 13 mm. respectively. In other words, 

 both in Apes and Lemurs the coronal sulcus is more oblique 

 and the area to its mesial side more extensive than in Neso- 

 pitliecus. In this particular Nesopithecus approximates nearer 

 to the primitive condition than either Lemur or Cercopitliecus. 



The position of the diagonal sulcus {e) is noteworthy. In the 

 Indrisinse this furrow is placed within the orbital depression, 

 i. e. below the orbital margin ; in Lemur it extends on to the 

 orbital margin, but is placed mainly in the orbital depression ; 

 whereas in Nesopithecus {Globilemu?') it is placed tvliolly above 

 the orbital margin. In this respect Glohilemur resembles the 

 Apes. 



The long furrow labelled g in the type-specimen (Mem. 

 figs. 39 and 40) is in the present one seen to consist of two 

 separate sulci — an obliquely-placed anterior element (y), the 

 upper extremity of which overlaps a small comma-shaped furrow 

 {g'). The latter almost certainly represents a " lateral " (intra- 

 parietal) sulcus. I cannot confidently express a definite opinion 

 as to the identity of the furrow labelled g, i. e. the anterior 

 oblique element; but the condition exhibited in this specimen 

 does not lend any support to the view that it is in any part of 

 the Sylvian fissure. Nor can I confidently regard it as a separate 

 part of the lateral, because such a breaking-up of that is almost 

 unknown, except in the Simiidse and Man. 



