So6 POPULAR SCIENCE MONTHLY 



Hamitie, the Greeks, who speak Aryan, and the Jews and Arabs, who 

 spoke Semitic, is simply due to the fact that those peoples, from having 

 long dwelt under practically similar conditions in the Mediterranean 

 basin, have gradually acquired that physical similarity which has led 

 Sergi to the assumption that they have a proximate common ancestry, 

 and that they accordingly form but a single race. 



Nor is there any lack of instances of convergence of type under 

 similar conditions in the case of the lower animals. We saw that the 

 asses of southwestern Asia approximate in color to the asses of north- 

 east Africa, and in respect of the size of the ears and absence of 

 shoulder stripe, more especially to the nearest of these, the ass of 

 Somaliland. Yet it does not follow that they are more closely related 

 to the Somali ass than they are to their own next neighbors, the kiang. 

 On the contrary, it is much more likely that the Somali ass is closely 

 related to those of Abyssinia, and that the southwestern Asiatic asses 

 are closely related to the kiang. The approximation in color, absence 

 of shoulder stripe and size of the ears between the asses of Somaliland 

 and those of southwestern Asia must rather be explained by a con- 

 vergence of types under the somewhat similar climatic conditions of 

 Somaliland and the nearest parts of southwestern Asia. Again, 

 though there are very strong, specific differences between the Grevy 

 and Burchelline zebras met in the neighborhood of Lake Barringo, 

 there is a curious approximation, not only in marking, but also in the 

 teeth between these two species, which is best accounted for by suppos- 

 ing that it is the outcome of similar environment. It may be said 

 that this approximation may be due to the interbreeding of the two 

 species of zebras in the region where they overlap. This, in itself a 

 most unlikely contingency from all that is known of the habits of wild 

 species, certainly can not be alleged in the case of the convergence in 

 type between the asses of southwestern Asia and the Somali ass, since 

 they are separated by the Ked Sea and the Persian Gulf. 



Again, the representative of the crocodile family in the Ganges is 

 distinguished by the extreme elongation of the head and jaws, whilst 

 the same elongation of the head is equally characteristic of the repre- 

 sentative of the dolphin family found in the same waters. Again, all 

 through the Indian Ocean wherever any family of crabs have become 

 inhabitants of coralline sands its members have long legs. Again, it 

 has long been noticed that in Cutch all the larger animals have a 

 tendency to become a sandy color, whilst in certain areas of South 

 America insects, no matter to what family they belong, have a tendency 

 to one common aspect. 



It may, of course, be said that the changes in color of the horse 

 family, tigers and insects are for " protective " reasons. But the 

 case of the horse family alone is sufficient to dispose of this objection. 



