1904.] OF THE POTTO AND SLOW LORIS. 159 



to be its typical form. It is quite diiierent in the other, and the 

 diflFerence is not without interest. As will be observed in the 

 accompanying drawing (text-fig. 11,/), the furrow in question is 

 really two f uri'ows, one ti'ansvei'se, the other longitudinal, arranged 

 triradiately. I think it not unreasonable to regard the tiunsverse 



Text-fig. 11. 



Dorsal aspect of brain of NycUcehus tardigradus. 

 d., see description in text ; /., tissure of Rolando ; s., Sylvian fissure. 



portion as the fissure of Rolando (Sulcus centralis), and the con- 

 ditions observable are distinctly more like those of the Potto (see 

 later, p. 160). These new facts account also, it will be observed, 

 for the somewhat anomalous bracket-like form of the fissure "/." 

 In both specimens and on both sides there was a small but very 

 clearly marked furrow (d, text-fig. 11) running across the interval 

 between the post-Sylvian and the post-lateral, and as nearly as 

 possible at right angles to both. Its direction is the same in both 

 specimens. 



Text-fig. 12. 



Lateral view of brain of Nycticehus tardigradus. 

 Letters as in text-fig. 11. 



Of Perodicticm jwtto fewei' bi'ains have been examined than 

 of Nycticehus, apparently only four, of which but two have been 

 figured, that described by myself and that described by both 

 Ziehen and Elliot Smith. One matter of interest that I am able 

 to record is the existence of a shallow depression traversed by a 

 blood-vessel, which seems to me to correspond to the post-lateral 

 sulcus of Nycticehus. Dr. Elliot Smith thinks that the sulcus 



