22 GENERAL REMARKS ON CAVE FAUNA. 



able vigorously to discriminate between the two. We shall ac- 

 cordingly look upon the subterranean fauna, or more properly 

 faunas, as small ramifications which have penetrated into the earth 

 from the geographically-limited faunas of the adjacent regions ; 

 and which, as they extended themselves into darkness, have been 

 accommodated to surrounding circumstances. Animals not far re- 

 mote from the ordinary forms, prepare the transition from light to 

 darkness. Next follow those that are constructed for twilight ; 

 and last of all those destined for total darkness, and whose struc- 

 ture is quite peculiar. Among these some are adapted for special 

 localities, those which inhabit dry localities or detached little 

 reservoirs being totally blind, while others, destined for running 

 streams, have eyes of imperfect construction, so as to receive the 

 impression of rays of light, but no proper image of illuminated 

 objects. We may therefore with tolerable precision arrange the 

 inhabitants of caverns under the following heads : 



Shade animals. Extensive genera and species inhabiting cav- 

 erns near their entrance, and, generally, all cool, shady and moist 

 localities. Of these, those that fly occasionally enter far into the 

 caverns (Diptera). 



Twilight animals. They belong to widely spread genera, but 

 are peculiar to the caves, and distinguished by their small eyes. 

 They are principally found near the entrances to the caves, but 

 proceed deeper into the darkness than the shade-animals, and 

 although wingless, they penetrate often the whole extent of the 

 dark space. (Pristonychus elegans, Homalota spelwa.) 



Cave animals. The^y form, at least in part, peculiar genera, are 

 wingless and colorless, as far as the consistency of their integu- 

 ments will admit, and exist exclusively in total darkness. The 

 terrestrial division is blind ; the aquatic has a perception of light. 

 To this group belong all the animals in the Mammoth Cave, and 

 among those of the caves of Carniola, Auoplithalmus, Bathyscia, 

 perhaps likewise Anurophorus and Hypochthon, which, however, 

 may belong to the following group. 



Stalactite cave animals. Insects, Arachnidans and Crustaceans 

 appertaining to peculiar genera, wingless, blind, brightly colored 

 according to the nature of their integuments, either light brown, 

 yellowish white, or snow white, perhaps according to the pre- 

 ponderance of the chitine ; living in total darkness, peculiar to 

 stalactite caves, in part occupying the columns and constructed 

 accordingly, either for ascent or hovering over them. Here belong 

 most of the animals treated of in this memoir Stagobius, Blo- 

 thrus, Stalita, Niphargus, and Titanethes." * 



A pertinent question arises as to the time of the formation of 

 these caves and when Lhey became inhabitable. As previously stat- 



*In a note appended he adds to the list "a new cave crustacean, Pnlomnn anopthal- 

 mus Kollar, said to serve as food for Hypochthon [the Salamander], of which last geuus 

 he discriminates six species." 



