1889.] 



THE YOUNG NATURALIST. 



69 



to-day as to-morrow will be. We know that all the life we see around 

 us is but a passing phase of time, that what we call species own no 

 such quality as endurance, and that perpetual change is implanted in 

 every natural form. We see from our brief point in time, some few 

 branches and twigs of the great tree of life, but its roots are hidden in 

 the abyss of ages, and of its ultimate leaf and flower we cannot even 

 conceive. And so, when in the light of such knowlege, we consider 

 the relation of those similar forms we distinguish as species, we are 

 led to conjecture that it is time and time alone that sunders form from 

 form ; that if we could see back into the ceons, we should discern 

 some shape that united species with species, some type in which 

 families were blended in one. That taking for instance the order we 

 are considering, we might find one form which united all the Geode- 

 phaga in itself, nay more, some insect creeping on the shore of some 

 dim Silurian sea, which bore in its own fabric the potentiality of all 

 coleopterous development. To trace the lines of Genesis, to trace 

 back the devious course of specialization of organ, this must be, we 

 think, the difficult task of future systematists. The exact form which 

 may have united Brachelytra and Geodephaga, to take two obviously 

 natural divisions, will probably be for ever hidden from our eyes, but 

 we can to-day trace their approximation, and guess that Dvomius and 

 Lebia may be ages older than Carabus or Cicendela, because they point 

 back to a divergent group, just as the nearer a branch of a tree ap- 

 proaches to union with a divergent branch, of necessity the older it 

 must be, for growth takes place at extremities, and complexity in- 

 creases with time. So again it might with some show of reason be 

 suggested that the Brachelytra were the oldest of all the Coleoptera, 

 because they approximate most to the Dermaptera ; but this view 

 might be again modified by embryological data, as Vermiform are 

 considered by many as undoubtedly lower than Hexapodal larval 

 forms. For divergent groups, as we have tried to explain, are united 

 not in linear but in ramific order, by the lowest terms of each, not by 

 the highest of the inferior group approximately to the lowest of the 

 the superior. Take, for example, the two great sub-kingdoms, Verte- 

 brata the superior, and Articulata the inferior. The lowest eel which 

 comes at the bottom of the Vertebrata, could not be more unlike a 

 Cicindela, which comes about the top of Articulata, but it approaches 

 closely to the Vermes or worms, which come at the bottom. So it is 

 with species, to discover their affinities it is necessary to study their 

 lowest phase, and that in the individual is the embryo. Even as in 

 the human embryo we recognise the links which bind us to a meaner 



