INSECTIVORA OF THE SANTA CRUZ BEDS. 367 



teriorly, while nr% is less reduced. In all the grinding teeth, upper and 

 lower, the cusps are early worn away, leaving more or less cordiform 

 masticating surfaces (PI. LXIV, Fig. 3*). 



As a whole, the dentition is both like and unlike that of Chrysochloris ; 

 the likeness is in the grinding teeth, the only noteworthy differences here 

 being the less completely hypsodont character, the absence of the internal 

 pillar in the upper teeth and the less extreme reduction of 1113 in both 

 jaws. The unlikeness is in the incisors, canines and foremost premolar, 

 which in Chrysochloris are all small and of similar form. In Notoryctes 

 the molars resemble those of the other two genera, but all the antemolars 

 are minute and have evidently been much reduced. 



The skull of Necrolestes is very similar indeed to that of Chrysochloris 

 and although it is, in most respects, less modified and peculiar and in a 

 few points more so, it is of an identical structural type. The skull is 

 longer and more tapering anteriorly than in the modern genus, and the 

 muzzle is prolonged in front of the incisors into a long, tapering, and up- 

 turned snout, which gives a very peculiar appearance to the whole head, 

 almost equally different from the short, broad, and abruptly truncated 

 muzzle of Notoryctes and the longer, narrower muzzle of Chrysochloris ; 

 the premaxillaries do not display the curious expansions seen in the lat- 

 ter, though this difference is apparent rather than real, for the processes 

 are concealed by the prolongation of the nasals, while in Chrysochloris 

 the shortened nasals leave them exposed. As in the African genus, the 

 -occiput is a broad, hemispherical swelling, somewhat less inflated, how- 

 ever, and without so distinct a depression in the median vertical line.. A 

 very short, but broad and distinct paroccipital process is present and en- 

 closes a deep fossa immediately behind the glenoid cavity. The occipital 

 condyles are notably large, especially in the transverse direction and the 

 foramen magnum presents less ventrally than in Chrysochloris. 



One very marked difference from the modern genus consists in the very 

 much less inflated and swollen character of the squamosal. In Chryso- 

 chloris this bone, seen from the front, looks like a sphere attached to the 

 side of the cranium, most of it internal to the zygomatic arch, but in the 

 fossil there is no such appearance. The zygomatic arch is long and quite 

 distinctly heavier than in Chrysochloris, but its root is not so expanded 

 into a vertical crest as in the latter, in which these processes have a pecu- 

 liar appearance of enfolding the skull and make the temporal fossae very 



