BRITISH ASSOCIATION: ZOOLOGICAL SECTION. 397 



descent, are we not justified in accusing morphology of having made 

 rather too much of the organs as units, as if they were concrete 

 instead of inducted abstract notions ? An organ which changes its 

 function may become a unit so different as to require a new definition. 

 And two originally different organs may come to resemble each other 

 so much in function and structure that they acquire the same defi- 

 nition as one new unit. To avoid this dilemma the morphologist 

 has, of course, introduced the differential of descent, whether homo- 

 logous or analogous, into his diagnoses of organs. 



The same principles must apply to the classification of the 

 animals. To group the various representative owners of cases of 

 isotely together under one name, simply because they have lost those 

 characters which distinguished their ancestors, would be subversive 

 of phyletic research. It is of the utmost significance that such 

 "convergences" (rather " mergers," to use an administrative term) 

 do take place, but that is another question. If it could be shown 

 that elephants in a restricted sense have been evolved independently 

 from two stems of family rank, the convergent terminals must not be 

 named Elephantince, nor can the representatives of successive stages 

 or horizons of a monophyletic family be designated and lumped to- 

 gether as subfamilies. And yet something like this practice has 

 been adopted from Cope by experienced zoologists with a complete 

 disregard of history, which is an inalienable and important element in 

 our science. 



This procedure is no sounder than would be the sorting of our 

 Cartwrights, Smiths, and Bakers of sorts into as many natural 

 families. It would be subversive of classification, the aim of which 

 is the sorting of a chaos into order. We must not upset the well- 

 defined relative meaning of the classificatory terms which have 

 become well-established conceptions ; but what such an assembly as 

 the terminal elephants should be called is a new question, the urgency 

 of which will soon become acute. It applies at leasjb to assemblies 

 of specific, generic, and family rank, for each of which grades a new 

 term, implying the principle of convergence, will have to be invented. 

 In some cases geographical terms may be an additional criterion. 

 Such terms will be not only most convenient, but they will at once 

 act as a warning not to use the component species for certain pur- 

 poses. There is, for instance, the case of Typhlops braminus, men- 

 tioned at the beginning of this Address. Another case is the dog 

 species, called Ganis familiar is, about which it is now the opinion of 

 the best authorities that the American dogs of sorts are the de- 

 scendants of the Coyote, while some Indian dogs are descendants of 

 a jackal, and others again are traceable to some wolf. The " dog," a 

 definable conception, has been invented many times, and in different 

 countries and out of different material. It is an association of con- 

 verged heterogeneous units. We have but a smile for those who 

 class whales with fishes, or the blindworm with the snakes ; not to 

 confound the Amphibian Coecilians with Reptilian Amphisbanas 

 requires some training ; but what are we to do with creatures who 

 have lost or assimilated all those differential characters which we 

 have got used to rely upon ? 



