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SCIENCE. 



[X. S. Vol. XXI. No. .3:50. 



rope and in Xorth America instead of forming 

 a single line of evolution there were at least 

 seven or eight nearly contemporary but dis- 

 tinct lines of rhinoceros succession, some of 

 which can be traced back as far as the base of 

 the middle Tertiary. The truly American 

 rhinoceroses which appear to have branched 

 out into several water-living, forest-living and 

 plains-living types, were reinforced by the 

 sudden appearance of the extremely short- 

 limbed rhinoceroses which had evolved in Eu- 

 rope and came over to this country simultane- 

 ously with the earliest elephants or mastodons. 



Another remarkable feature of this law of 

 multiple evolution is that even where these 

 varieties have evolved quite separatel.y and 

 independently, they still have inherited from 

 remote common ancestors certain tendencies 

 or potentialities of evolution which were latent 

 but not expressed in the ancestral forms but 

 which find a more or less simultaneous ex- 

 pression in the derived forms. Thus, among 

 the rhinoceroses and titanotheres the rudi- 

 ments of horns begin to appear more or less 

 simultaneously in several of these multiple 

 independent races or varieties, indicating a 

 hereditary predisposition toward the develop- 

 ment of certain organs quite unsuspected in 

 the earlier evolutionary writings of Lamarck 

 and Darwin. This predisposition to evolve 

 certain structures tends to establish the idea 

 that the laws of development are not con- 

 trolled solely by the survival of the fittest as 

 according to the original Darwinian theory, 

 nor by the inherited effects of use and disuse 

 as according to the Lamack-Spencer theory, 

 but represent the budding out or expression 

 of certain innate or inherited ancestral tend- 

 encies. 



Among the greatest surprises in recent dis- 

 covery has been the finding of armadillo-like 

 edentates in the Rocky Mountain region near 

 Ft. Bridger, Wyo., from rocks of the lower 

 Tertiary period. These armadillos certainly 

 bore a leathery if not a bony shield. Some 

 ossicles indicating the presence of the bony 

 shield are reported to be present in the collec- 

 tions of the Yale Museum ; the remains thus 

 far found by the American Museum exploring 

 parties show a provision for the shield in the 



structure of the backbone but do not exhibit 

 the bony elements of the shield itself. 



Almost equally surprising results of ten 

 years' exploration are the tracing back of the 

 dog family into the Lower Eocene, of the saber- 

 tooth tiger family into the Middle Eocene, 

 of the camel family into the Upper Eocene, 

 of the hedge-hogs (now extinct in this coun- 

 ti'y) into the Lower Oligocene, of the raccoon^ 

 into the Lower Miocene. The camel family, 

 like the horses and the rhinoceroses, branched 

 out into a great many varieties, short- and 

 long-limbed, most remarkable among the lat- 

 ter being the giraffe-camel (Alticamelus), 

 which, although a true camel, was closely 

 similar in build to the giraffe. With these 

 discoveries the names of Scott, \Yortman and 

 Matthew are honorably associated. 



It has long been known that the deer, bear, 

 moose, the oxen and sheep families did not 

 appear in this country until very late in geo- 

 logical times, shortly before the Ice Age. 



Among the many difiicult and still unsolved 

 problems is the cause of the total extinction 

 of the horse in North and South America 

 while it survived and multiplied in Europe, 

 Asia and Africa. Just before the time of the 

 extinction of the horse, America exhibited the 

 greatest beauty and variety in the develop- 

 ment of this family. As studied by Gidley, 

 there were horses exceeding in size the enor- 

 mous Percherons of to-day and there were also 

 varieties smaller than the most diminutive 

 Shetlands. Yet with all this wide range of 

 variation all became extinct. 



The elephants also exhibited three great 

 varieties, the true mammoth (E. primigenius) 

 to the north, the Columbian elephant in the 

 central states, and the gigantic Imperial mam- 

 moth to the south, forms shown to be quite 

 distinct by Lucas and undoubtedly adapted to 

 various kinds of climate ; yet all died out with 

 the great wave of death which swept off the 

 camels, horses and the giant. South American 

 sloths, just before or during the first advance 

 of the Glacial period. H. F. O. 



SriKyTTFia NOTEf? A^'D NEWS. 

 The senate of the Fniversity of Edinburgh 

 has voted to confer its honorary doctorate of 



