380 PATAGONIAN EXPEDITIONS: PALAEONTOLOGY. 



Chrysochloris, but the humerus is almost exactly as in the latter, as are 

 also the forearm bones, even to the ossification of the flexor tendon. 



The manus is very much less reduced and specialized than in the 

 African genus; the carpals, metacarpals and phalanges are present in 

 nearly or quite their normal numbers and the digits were apparently five 

 and of approximately equal size. The ungual phalanges are all of similar 

 type, that of the third digit not being greatly enlarged, nor the others much 

 reduced. It is evident that Necrolestes cannot have been so thoroughly 

 well adapted to burrowing habits as is Chrysoc Moris, though the structure 

 of the arm and forearm shows, that it was fossorial. Different as the 

 manus is in the two genera, the plan of structure is the same in both and 

 that of Chrysochloris may well have been derived from a type like that 

 of Necrolestes. 



The pelvis of the Patagonian genus is not altogether unlike that of the 

 African, but it is much less modified, as is to be seen in the large size of 

 the pubes and of the obturator foramina. The hind leg and foot are, how- 

 ever, quite peculiar and appear to have been specialized in a manner dif- 

 ferent from that characterizing any of the modern families of Insectivora. 



Another consideration which renders it probable that Necrolestes itself, 

 or its immediate ancestor, was an immigrant from Africa, is the entirely 

 isolated position of this genus in the Santa Cruz fauna. Of course, it 

 might have been the last remnant of a once numerous group, but no 

 allies, or near relations, or probable ancestors have been found in any of 

 the pre-Santa Cruzian formations. Had the family been a truly indigenous 

 one, we should undoubtedly find a greater or less number of allied genera, 

 as is the case with all the other orders represented in the Santa Cruz 

 beds, but Necrolestes stands quite alone, a fact which is explicable only 

 on the assumption that it is an immigrant. 



It is not suggested that Necrolestes is to be regarded as the ancestor of 

 any of the existing Chrysochloridce, for it is itself specialized in a different, 

 though moderate way. What does seem probable is that Necrolestes is 

 an offshoot from some early member of the family which was at the same 

 time the ancestor of Chrysochloris. If this conclusion is correct, it will 

 lead to the further inference that the family originated in the Southern 

 Hemisphere, and will militate against the view that the Cape golden 

 moles are allied to the true moles. The resemblances, neither many nor 

 close, between the two families are much more probably the results of 



