226 ANNALS NEW YORK ACADEMY OF SCIENCES 



Oligocene and Miocene of Europe by more primitive ancestral forms. A 

 relatively primitive genus, Proterioc, occurs in the Oligocene of South 

 Dakota, as a contemporary with more progressive genera in the Oligocene 

 of Europe. The family is otherwise unknown in the New World. 



The moles and shrews are also evidently of northern origin. Of the 

 two families, the Soricidip are more primitive in structure and have 

 spread more widely; the more specialized Talpidne are still limited to 

 Holarctica, and in the extreme north their exclusion from the areas of 

 permanently frozen subsoil has split their range into two disconnected 

 areas. The most progressive and abundant shrews are ITolarctic, while 

 the Oriental and African species (Crocidurinoe) retain some primitive 

 characters. Fossil moles and shrews in the middle Tertiary of Europe 

 and America indicate that the divergence between the two families was 

 not then so great as now. The modern genera are reported to occur 

 (but on inadequate evidence) as early as the Miocene in Europe and 

 America. Jaws of several minute talpoid genera are known from the 

 Middle and Lower Eocene of North America. They are unknown in the 

 extra-Holarctic Tertiary, but this negative evidence is of no weight in 

 view of their minute size and rarity. 



The Tupaiidffi of the East Indies and Macroscelididas of Africa occupy 

 a somewhat anomalous position, since they are of higher type in brain 

 development than other Insectivora and in many respects are nearer to 

 the higher placental mammals.^^ Their distribution so remote from the 

 great northern dispersal center may perhaps best be accounted for by 

 considering the fact that their specializations, adaptations and habits of 

 life are of a less unusual kind than in most of the lower insectivores and 

 would bring them more directly into rivalry with certain groups of 

 rodents, with which they were unable to contend successfully and were 

 compelled to retreat southward in consequence. No fossil remains cer- 

 tainly referable to these families are known, although quite a number 

 of early Tertiary genera of Europe and North America have been or 

 might be provisionally referred to them.**- 



There are a large number of primitive Insectivora in the Eocene of 

 North America and a few in Europe, which do not seem to be nearly 

 ancestral to any modern group but rather indicate that the order once 



**This anomaly in distribution is now removed by tbe studies of Gregory and Elliott 

 Smith, which show that the true relations of Tupaia and presumably of Macroscelides, 

 are with the Primates, rather than with the Insectivora. Their geographic distribution 

 Is quite normal on this view of their affinities. 



** Entomolestes of the Middle Eocene of North America is regarded by Dr. Gregory as 

 probably related to Tupaia, and a number of other small mammals from tbe Bridger and 

 Wasatch may be related to this group of Insectivora. 



