NERVOUS SYSTEM. VBRTBBRATA. 369 



cases the lower part of the Sylvian fissure is shallow, and at 

 the point where the shallow part ("feline Sylvian ") joins 

 the deep part (suprasylvian) the lower extremity of the 

 suprasylvian sulcus may be seen emerging so as to cut 

 into the anterior lip of the fissure. [It is only right to 

 inform the reader that these views are here put forward 

 for the first time, and are in direct conflict with the usual 

 teaching.] 



The lateral (intraparietal) sulcus forms an arc around 

 the Sylvian fissure, as it does in Daulentonia. Behind it 

 there is a small postlateral or, as we now should probably 

 call it, " transverse occipital " sulcus. 



The crucial sulcus of the Carnivora is apparently repre- 

 sented by a small pit on the dorsal surface (figs. 210 and 

 211, Y), which may perhaps be regarded as the first rudi- 

 ment of the sulcus centralis (Rolandi) of the Primates *. 



The intrepretation of a well-marked sagittal sulcus on 

 the dorso-lateral aspect of the front part of the hemisphere 

 raises a question of great difficulty. For reasons which 

 cannot be stated in full here (but which will be apparent 

 if the reader refers to the brains of Procavia and Viverra), 

 this furrow (SULC. RBCT.) is almost certainly the coronal. 



On the other hand, it is regarded as the representative of 

 the sulcus rectus of the Apes, which in turn is considered 

 by Eberstaller and many others as the homologue of the 

 sulcus frontalis medius, and by Cunningham as the sulcus 

 frontalis inferior. If the tendencies which are to be noted 

 in the evolution of the lowlier Primate brain continue to 

 exercise their influence in the Anthropoidea (and in this 

 matter they unquestionably do), there can be little doubt 

 as to the accuracy of Cunningham's interpretation f. 



* It is difficult to be otherwise than sceptical concerning the suggestion 

 of this being sulcus centralis, although it occupies the position where we 

 find the earliest rudiment of the central sulcus in the Cebidfe. The only 

 other sulcus it can possibly be is the ramus postcentralis superior of the 

 intraparietal sulcus. A careful study of the whole series of Primate brains, 

 however, seems to point to the conclusion that the sulcus Y represents the 

 upper part of the sulcus of Rolando. 



f The sulcus in question probably represents the conjoint sulci rectus 

 (inferior frontal) and arcuatus (inferior precentral) of the Apes. 



VOL. II. ^ B 



