270 PHYSIOLOGICAL SERIES. 



smooth brains of the Rodent, Insect! vore, and Marsupial 

 Orders they still present the typical Carnivore pattern of 

 sulci. The pattern exhibited by these sulci essentially 

 conforms to the Arctoid type. 



The pseudosylvian sulcus corresponds to that of the 



Procyonida? and not to that of the Dogs and Cats ; the 



suprasylvian arc is acutely flexed ; the lateral and coronal 



form one simple sulcus ; there is neither an ansate nor a 



postlateral sulcus ; there is a large transverse crucial sulcus 



but no definite precrucial. There is a large orbital 



sulcus. O.C. 1325 (.. 



Presented respectively by Dr. Rolleston (tin I 



R. F. Tomes i 



Mivart, Journ. Linn. Soc., vol. xix. 1886, p. 17. 



Holl, Arch. f. Anat. u. Entwick. 1899, p. 239. 



D. 350. The brain of a Glutton or Wolverine (Gulo 



The typical Arctoid features are well shown in this 

 specimen : the long " Sylvian fissure " encircled by the 

 acutely flexed suprasylvian arc ; the long crucial sulcus 

 which does not join the cephalic prolongation of the 

 calcarine (splenial) sulcus ; and the large precrucial sulcus 

 and consequently a well-defined Ursine lozenge. 



The extensive postlateral joins the lateral sulcus and 

 from the latter a large ansate extends forward. A large 

 sulcus on the lateral side of the ansate is obviously a com- 

 pensatory ansate sulcus; it opens into the great crucial 

 sulcus. The coronal is not joined to the lateral. 



On the left side the lips of the pseudosylvian sulcus have 

 been removed to show the region of the " Sylvian trigoin- " 

 and the first arcuate gyrus. 



The cephalic prolongation of the calcarine is very short, 

 as in the Bears and Seals. There is a short vertical genual 

 sulcus. There is a long, deep, vertical postcalcarine. 



In front of the crucial sulcus there is a sagittal prorcan 

 sulcus on the dorsal surface of the hemisphere. 



Note the peculiar square shape of the posterior part of 

 the hemisphere. 



I'.cddard, 1'roc. Zool. Soc. 1895, p. 139. 



