406 PHYSIOLOGICAL SERIES. 



The collateral sulcus is represented by two deep sulci. 



Tin* stik-i rectus et arcuatus are concurrent. 



There is a small superior precentral sulcus. 



External to the orbital sulcus there is now a definite 

 fronto-orbital (anterior limiting) sulcus. The floccular 

 lobes of the cerebellum, which closely resemble those of 

 Alonatta (D. 572), are particularly well-demonstrated. The 

 vermiform flocculus alongside the auditory nerve is very 

 distinct, and the peculiar club-shaped " petrosal lobule " of 

 the paraflocculus presents very well-marked features. 



0. C. 1337 1. 



D. 587. The brain of a Humboldt's Woolly Monkey (Lagothrix 

 lunnuoldti). The left hemisphere is detached. 



The peculiar features of the parieto-occipital and intra- 

 parietal sulci are found here also. The posterior ramus of 

 the triradiate intraparietal sulcus is separated from the 

 Affenspalte by a wide gyrus, especially on the right side. 



The posterior sulcus compensatory to the Simian sulcus 

 is much larger than in the last specimen. Nevertheless the 

 lateral occipital sulcus is well-developed. The result of 

 this, however, is that the inferior occipital sulcus is poorly 

 developed, but there is a compensatory deepening of the 

 anterior segment of the collateral sulcus. 



On the right hemisphere the dual nature of the conjoint 

 sulci rectus et arcuatus is indicated by a submerged gyrus. 

 On the left hemisphere, however, the conjoint sulci form an 

 irregular crucial pattern. 



The inferior temporal sulcus is unusually well-developed. 



0. C. 1337 I a. 



D. 588. The brain of a Black-faced Spider-Monkey (A teles atcr). 

 The condition of the parieto-occipital and intraparietal 

 .-u lei is essentially identical with that just described in 

 Lagothrix. But the inferior limb of the triradiate intra- 

 parietal seeing, at a casual glance, to actually join the Sylviau 

 fissure. But in reality it ends behind the upper extremity 

 of the Sylvian fissure, as in Lagothrix, and is separated 

 from the latter only by a deeply submerged gyrus. On 

 the right side the ramus postcentralis superior is united to 



