;;:36 peop. g. Elliot smith ox the 



These measurements are extraordinarily lari^e "when it is considered that the hrain 

 weighed only 26'3 grms., after heing in 10 per cent, formol solution for eight days. 



The corresponding measurements in an adult female L. macaco I found to he 

 t3 mm., 37 mm., and 2C mm. respectively. These measurements (which were checked 

 hy comparison with the cranium) indicate a brain-shape very different to that of Elatau 

 and Jacohsohn's specimen. If the latter were swollen as the result of the formalin, the 

 value of the elaborate tables of measurements in their book is seriously discounted. 



The hemispheres of a Lemur fiilvtis were 46 mm. long and 38 mm. broad ; and the 

 corresponding measurements in a Lemur varius were 49 mm. and 43 mm. respectively. 



The size of the brain of the extinct Lemur Jullyi greatly exceeded that of any of the 

 recent Lemurs; for its cerebral hemispheres were 59 mm. long, 48 mm. broad, and 

 31 mm. deep. 



Turning to the consideration of the cerebral sulci and fissures, a considerable amount 

 of variation is found. 



The rhinal fissure usually becomes aborted, with the exception of a very small furrow 

 near the olfactory peduncle and the apparent recurved inferior extremity of the pseudo- 

 sylvian sulcus. In the specimen of Lemur fulvus described above, the greater part of 

 the fissure persisted. In another specimen of L. fulvus, and in one each of L. macaco 

 and L. varius, I have seen a faintly marked furrow representing the whole fissure. 



The two brains of L. varius (one in the College of Surgeons and one from Ghizeli) 

 agree in the following respects : — The diagonal sulcus is absent ; the orbital sulcus is so 

 poorly developed as to be a mere insignificant depression ; the lateral sulcus is a simple 

 regular arc, widely separated from the postlateral and coronal sulci ; the sulcus d is not 

 joined to either the supra- or to the postsylvian sulcus ; the collateral sulcus is very small 

 and shallow ; and, apart from the small floccular sulcus, there is no sulcus behind the 

 postsylvian. 



All of these features may be regarded as indicative of a tendency to simplicity, which 

 is all the more significant in that the brain in tliis species is appreciably larger than that 

 of most other members of the genus. It remains for future research to determine 

 Avhcther these features may be regarded as distinctive of the species varius. 



I have examined two brains of Lemur macaco and several cranial casts. In addition 

 Platan and Jacobsohn [op. cit.) have given a full description of a brain of this species. 



The diagonal and orbital sulci are constantly present, but the latter shows a tendency 

 to become irregular by the development of a lateral ranuis. Sometimes also its direction 

 varies. The mode of ending of the upper extremities of the supra- and postsylvian 

 sulci is variable. In most cases the upper extreinity of the suprasylvian sulcus is 

 simple ; but Platan and Jacobsohn represent (Taf. 3. fig. 1, -^j a small added horizontal 

 sulcus. Generally the upper end of the i)arallel sulcus curves forward, representing a 

 fusion with the sulcus d, which usually does not exist as a separate element in this 

 species. Unlike the condition found in L. varius, there is no distinct postlateral sulcus, 

 but there is a very ol)lique furrow, united at a very obtuse angle with the caudal end of 

 the lateral sulcus. 



1 have never seen the sulcus described as " temporalis sccuiidus (oberer Teil) " by 



