INSECTIVORA OF THE SANTA CRUZ BEDS. 369 



or notch, which receives the lower canine when the jaws are closed. 

 The bony palate differs in several important respects from that of Chryso- 

 chloris, though having a similar general character and shape, since it does 

 not take part in the snout-like prolongation of the muzzle, which is all in 

 front of the incisors and is formed chiefly by the nasals. The incisive 

 foramina are conspicuous and are long, narrow slits, running nearly the 

 whole length of the palatine processes of the premaxillaries and separated 

 by a slender spine. In Chrysochloris these foramina are either obsolete 

 or exceedingly minute. The maxillary portion of the palate is broad and 

 is traversed by obscurely marked, curved ridges, with the convexity 

 turned forward, these ridges resemble and doubtless correspond to those 

 of the soft palate. The posterior ^nares have the same relative position 

 as in the African genus, but are rather higher and broader and they are 

 divided into two openings by an extension of the vomer throughout their 

 length, which descends to the level of the bony palate and is united with 

 the palatines in the median line of the front margin of the narial opening, 

 making the vomer appear like a process of the palatines. This extension 

 of the vomer is not found in Chrysochloris. The pterygoid fossae are not 

 completely suppressed, as in the latter genus, but are represented only by 

 shallow and inconspicuous grooves. 



The mandible is exceedingly like that of Chrysochloris, so much so as 

 immediately to suggest a relationship between the two genera, but it dif- 

 fers in a few minor details. The horizontal ramus is relatively longer and 

 -has a more sinuous ventral border, while the rami of the two sides are 

 somewhat less widely separated, converge more gradually forward and 

 meet in a rather longer symphysis. The coronoid process is higher, 

 broader, and more inclined backward, so that the sigmoid notch is not as 

 widely open. The condyle is set upon a similarly elongated neck and is 

 a transverse semicylinder, but the masseteric fossa, which is barely indi- 

 cated in the modern genus, is quite deep and has a raised anterior border, 

 though the fossa is small and placed high upon the ascending ramus. 

 Doubtless the better development of the masseteric fossa in Necrolestes is 

 to be correlated with the stouter zygomatic arch. The angle is decid- 

 edly smaller and more hook-shaped and has no tendency whatever to 

 inflection. 



The cranial foramina are difficult to make out in such a small skull. 

 Such as are visible, however, are suggestively like those of Chrysochloris. 



