26 ORIGIN OF CAVE LIFE. 



Assuming on the principles of evolution that the cave animals 

 were derived from other species changed by migration from the 

 outer world to the new and strange regions of total darkness, it 

 seems evident that geologically speaking the species were suddenly 

 formed, though the changes may not have been wrought Until after 

 several thousand generations. According to the doctrine of natu- 

 ral selection, by which species pass from one into another by 

 a great number of minute variations, this time was not sufficient for 

 the production of even a species, to say nothing of a genus. But 

 the comparatively sudden creation of these cave animals affords, it 

 seems to us, a very strong argument for the theory of Cope and 

 Hyatt of creation by acceleration and retardation, x which has been 

 fully set forth in this journal. The strongly marked characters 

 which separate these animals from their allies in the sunlight, are 

 just those fitting them for their cave life and those which we would 

 imagine would be the first to be acquired by them on being re- 

 moved from their normal habitat. 



On introducing the wingless locust, Ceuthophilus maculatus, 

 into a cave, where it must live not under stones, but by clinging to 

 the walls, its legs would tend to grow longer, its antennae and 

 palpi would elongate and become more delicate organs of hearing 

 as well as touch,* and the body would bleach partially out, as we 

 find to be the case in H. subterranea and C. stygia. The Carabid 

 beetle, Anopthalmus, extending farther into the cave, would lose 

 its wings (all cave insects except the Dipterahave no wings, elytra 

 excepted) and eyes, but as nearly all the family are retiring in 

 their habits, the species hiding under stones, its form would not 

 undergo farther striking modification. So with the blind Campo- 

 dea, which does not differ from its blind congeners, which live 

 more or less in the twilight, except in its antennae becoming 

 longer. The blind Adelops, but with rudiments of eyes, does not 

 greatly depart in habits from Catops, while on the other hand the 

 remarkable Stagobius of the Illyrian caves, which according to 



* After writing this article, and without knowledge of his views, we turned to Darwin's 

 Origin of Species to learn what he had to say on the origin of cave animals. He attri 

 butes their loss of sight to disuse, and remarks :" By the time an animal has reached, 

 after numberless generations, the deepest recesses, disuse will on this view have more 

 or less perfectly obliterated its eyes, and natural selection will often have effected 

 other changes, such as an increase in the length of the antenna? or palpi, as a compen- 

 sation for blindness." 5th Amer. Edit., p. 143. We are glad to find our views as to the 

 increase in the length of the antennae and palpi compensating for the loss of eyesight, 

 confirmed by Mr. Darwin. 



