OF WASHINGTON. 15 



stumps is in no way abated. He has not accustomed himself to 

 any other diet than decaying vegetable matter, and he has devel 

 oped no very acute preferences regarding the origin or quality of 

 this simple provender. Back in the Carboniferous or before, he 

 made a single invention of sufficient effectiveness to secure immu 

 nity from molestation until the advent of the nineteenth century 

 naturalist. He anticipated, in fact, the warfare of the future, and 

 is prepared to deliver broadsides of prussic acid and other noxious 

 substances,* which render him an unpleasant companion and an 

 unpalatable morsel. But notwithstanding this effective equip 

 ment he has remained an anti-expansionist. Others have striven 

 for possession of the earth, air, and water, while he continues to 

 live because he can subsist on what is not useful to his more enter 

 prising relatives. 



Food being plentiful and unvaried, he has had no need to fol 

 low the insects in specialized mouth parts. Having no enemies, 

 .and living in concealment, he cannot be accused of mimicry or 

 other ruses for self-preservation. He has not invited destruction 

 by injuring others, nor overreached himself by attempting to 

 increase too fast, and thus destroyed his own means of subsist 

 ence. His eyes, when not altogether wanting, are only useful 

 in his efforts to keep from exposure to light, which is soon fatal ; 

 perhaps it poisons him by disintegrating his defensive ammunition. 

 He cannot be seen by his mate, so that sexual selection cannot be 

 invoked to explain his bright colors, f nor can these be looked 

 upon as warnings to enemies, since he leaves concealment only 

 at night. 



The diplopod has, in short, been exceedingly careful to keep 

 outside the undignified struggle for existence. If he has become 

 differentiated, it is on his own motion and not as a concession to 

 enemies or adverse circumstances. The Diplopoda offer, perhaps, 

 the finest of opportunities for the study of variation accumulated 

 without interposition of the principles of selection. Without 

 the introduction of diversity into the life-history of the organism, 

 there have come into existence numerous groups showing great 

 and constant structural differences, but each apparently filling 

 with equal success the same place in the economy of nature. 



In the insects we find numerous adaptations of obvious utility 

 occurring within ordinal and even within family limits, but in the 

 diplopods similar reasoning finds but the slightest application. 

 Drawings illustrating the peculiar characters of some members of 

 the African family OxydesmidaB are submitted herewith. J While 



* Science, N. S., XII, 516-520, October 5, 1900. 



t Eyes are entirely wanting in the large order Merocheta, to which be 

 long nearly all the bright-colored species. 



To be published elsewhere with a revision of the Oxydesmidae. 



