158 MR. F. E. BEDDARD ON BRAINS [Jan. 19, 



of students of the brain upon these Lemurs, since I have two new 

 brains of Nycticebus and one of Perodicticus to report upon, none 

 of which has been studied by any other person. 



Of Nycticebus tardiyradus eight brains * altogether have been 

 examined, one by Sir Wilham Flower t, one by myself +, four by 

 Ziehen §, one by Ohudziaski li, and one by Flatau and Jacobsohn^. 



The measurements of the cerebral hemispheres of my two new 

 brains are as follows : — 



A. Length 30 mm., greatest diameter 26 mm., height 20 mm. 



B. ,, 26 mm., „ „ 26 mm., ,, 19 mm. 



I could detect no trace whatsoever of a distinction between an 

 upper supra- Sylvian sulcus and a lower pseudo-Sylvian sulcus 

 such as Dr. Elliot Smith describes and figures ; nor could I see the 

 little forwardly projecting end of the Sylvian which he figures in 

 the latei-al view of the brain. I observed in my brain A (the 

 larger of the two) that at the point where the Sylvian sulcus 

 becomes continuous with the lateral sulcus, the latter has a minute 

 forwardly directed continuation, which may be considered to 

 represent the anterior half of this fissure in Perodicticus ; and I 

 may call attention to the interesting fact that Dr. Elliot Smith 

 has himself figured in the Potto ** a feeble union between the 

 Sylvian and the lateiul fissures. The lateral fissure exhibits a 

 slight difference in direction in the two brains which I have 

 studied. In the smaller one the two fissures are distinctly more 

 parallel to each other and therefore to the interhemispheral sulcus. 

 In I'egai'd to the relations between the lateral sulcus and the post- 

 lateral (= my " parieto-occipital ") Dr. Elliot Smith writes: — 

 " It is interesting to note in these two casts [of the brain-cavity 

 of Nycticebus] that thei-e is a definite post-lateral sulcus in all four 

 hemispheres, and in none of them is the caudal extremity of the 

 lateral sulcus bent inward, as is invariably the case when the 

 separate post-lateral sulcus is absent. A comparison of the brain- 

 case of my type specimen with the other cranium fi'om Ghizeh 

 shows that the separate post-lateral sulcus occupies the same 

 position in I'egard to the skull as the mesially bent end of the 

 lateral sulcus of the other specimen " ft- In the two brains examined 

 by myself and reported upon hei-e, the caudal extremity of the 

 lateral sulcus is bent inwards (more in one brain than in the other) 

 and the post-lateral sulcus is well developed. In both bi'ains the 

 sulci are developed on both sides, and they just dip over the inter- 

 hemisphei'al margin lying there midway Toetween the two parts of 

 the calcai-ine fissure. The fissure which Dr. Elliot Smith lettei's "/" 

 is bracket-shaped in the smaller of my two brains, which appears 



* One of these lias been described botb by Ziehen and by Elliot Smith. 

 t " On the Brain of the Javan Loris," Tr. Z. S. vol. v. p. 103. 

 X Loc. cit. p. 144. § Loc. cit. p. 902. 



II Bull. Soc. d'Antbr. 1895, p. 436. 



^ Handbuch d. Anatomie . . . . d. Centralnervensystenis d. Saugethiere, Berlin, 

 1899. 

 **'Cat. Phys. Ser. Royal Coll. Suro:. p. 378, Hg. 220. 

 ■(-f Trans. Linn. Soc. loc. cit. p. 343. 



