506 TRANSACTIONS OF SECTION D. 
osmotic, ‘as in the naked Amphibia, it may evolve external gills. Nay, the whole . 
surface of the body may become so osmotic that both lungs and gills are sup- 
pressed, and the oreature breathes in a most pseudo-primitive fashion. This 
arrangement, more or less advanced, occurs in many Urodeles, both American 
and European, belonging to several sub-families, but not in every species of the 
various genera. It is therefore a case of apparently recent Isotely. 
There is no prejudice in the making of a new organ except in so far that 
every organism is conservative, clinging to what it or its ancestors have learnt or 
acquired, which it therefore seeks to recapitulate. Thus in the vertebrata the 
customary place for respiratory organs is the pharyngeal region. Every organism, 
of course, has an enormous back history; it may have had to use every part in 
every conceivable way, and it may thereby have been trained to such an 
extent as to yield almost at once, like a bridle-wise horse to some new stimulus, 
and thus initiate an organ straight to the point. 
Considering that organs put to the same use are so very often the result of 
analogous adaptation, homoplasts with or without affinity of 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 definition as 
one new unit. To avoid this dilemma the morphologist has, of course, intro- 
duced the differential of descent, whether homologous 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 signifi- 
cance 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 Hlephantine, nor can the 
representatives of successive stages or horizons of a monophyletic family be 
designated and lumped together 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 sub- 
versive 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 least 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 7'yphlops braminus, mentioned at the 
beginning of this address. Another case is the dog species, called Canis 
familiaris, about which it is now the opinion of the best authorities that the 
American dogs of sorts are the descendants 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 converged 
heterogeneous units. We have but a smile for those who class whales with fishes, 
or the blind-worm with the snakes; not to confound the Amphibian Cecilians 
with Reptilian Amphisbeenas 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? 
In a homogeneous crowd of people we are attracted by their little differences, 
taking their really important agreements for granted; in a compound crowd we 
a ato 
