MODERN SYSTEMS. 301 



precision in four kinds of groups in natural history, which 

 he calls classes, orders, genera, and species. 



Aristotle, and the ancient philosophers generally, dis- 

 tinguish only two kinds of groups among animals, 761/09 

 and elSo? (genus and species). But the term genus had a 

 most unequal meaning, applying at times indiscriminately 

 to any extensive group of species, and designating even 

 what we now call classes as well as any other minor group. 

 In the sense of class it is taken in the following case : 



Xeyw Be 761/09, olov opvt,6a, real lyQvv (Arist., Hist. Anim., Lib. 



I, Chap. I), while eISo9 is generally used for species, as the 



following sentence shows : Kal ea-riv e/iBi] Tfh-eiw l-^dvwv teal 



opviOwv, though it has occasionally also a wider meaning. 

 The sixth chapter of the same book is the most important 

 in the whole work of Aristotle upon this subject, as it 

 shows to how many different kinds of groups the term 

 76^09 is applied. Here he distinguishes between 



jiara and yew) fjieyciXa and 761/09 shortly. Tevrj Be 



TWV fjL>u)v, 6t9 a Biatpeirai raX\a ,u>a, raS' ea-rtv ev fiev opvidwv, 



ev B 1 l-^Qvwv, aAAo Be KIJTOVS. "AXXo Be 761/09 ecrrl TO rwv ocrrpa- 



Ko8ep/j,cov Twv Be XoiTrcoy faatv ov/c eart ra <yevr) /j,6<yd\a' 



ov jap Trepie^ei 7ro\\a eiBr) ev elBos, . . . . ra B' ey^ei pev, a 



This is further insisted upon anew : rov Be 



TeTpcnroBwv fyJacov teal 'CfAWTOKutv e'lBrj fjiev elcn 7r6\\a, avcavv/^a 



Be. Here ^809 has evidently a wider meaning than our 

 term species ; and the accurate Scaliger translates it by 

 genus medium, in contradistinction to 76^09, which he ren- 

 ders by genus summum. EISo9, however, is generally used 

 for species, in the same sense as we now distinguish them ; 

 and Aristotle already considers fecundity as a specific 

 character, when he says, of the Hemionos, that it is called 

 so from its likeness to the Ass, and not because it is of 

 the same species; for, he adds, they copulate and propa- 



