318 PHYSIOLOGICAL SERIES. 



hemisphere of the last specimen, has formed a definite 

 " pseudosylvian fissure." 



This confirms the view of Holl that the Ungulate 

 pseudosylvian sulcus is formed by the homologues of the 

 ectosylvian sulci of Carnivores. 



This is but one more example of the morphological 

 instability of the so-called " Sylvian fissure," of which the 

 Carnivora and especially the Ungulata afford so many 

 examples. 0. C. 1328 K a. 



Family DICOTYLID^K. 



D. 414. The brain of a Collared Peccary ( Tuyassutajagu), ( ? ). 



According to Garrod (Trans. Zool. Soc. vol. xi. 1879, 

 p. 13) the brain of Tayassu does not resemble that of the 

 true Swine so closely as Krueg suggests. The arrangement 

 of the orbital sulcus is like that seen in the Wart-Hog ; and 

 the so-called l " Sylvian fissure," which is here very 

 insignificant, finds its closest analogue in Phacoc/ta-rus. 

 The postsylvian sulcus is quite wanting. 



There is a complete cingular arc of fused calcarine, 

 intercalary, and genual sulci, as in the Tapir. This is 

 joined (on the right side only) to the coronal sulcus. Inn 

 is not prolonged into the latter, as is the case in the Swine 

 family. There is a cephalic prolongation of the lateral 

 sulcus midway between the coronal and suprasylvian sulci. 

 There is also a well-defined entolateral sulcus. 



0.0. 1828 M, 



Krueg, Zeitsch. f. wiss. Zool., Bd. xxxi. 1*7*, p. 323. 



D. 415. The brain of a Collared Peccary ( '/',I>/,IMH taja$u), 



In this smaller specimen the "Sylvian fissure-" is more 

 pronounced. 



The Slllcus hetsvecn the coronal and snprasylvian sulci is 

 much shorter. 0. C. I'M* M . 



D. 416. The brain of a Collared Peccary (Tayassu taja$u). 



No " Sylvian fissure" can be seen, but the upper lip of 

 the rhinal fissure is much puckered by numerous small 

 sulci, especially on the right hemisphere. 0. C. 1328 M b. 



