Fauna Subterranean. 155 



The circumstance of all the proper cave animals belonging to 

 those groups which feed on prey or else on fermenting vegetable 

 and animal substances, corresponds exactly with the nature of the 

 caves. For, all the caves in which these animals are known to 

 occur, agree in this, that they contain, more or less, running 

 streams, or at any rate accumulations of water, which may be sup- 

 posed to receive influx from without. It is easy, therefore, to 

 understand how the aquatic animals obtain their food. But water 

 will also carry with it sufficient food for the land animals of the 

 caves, consisting of living and dead animals, and putrid vegetable 

 substances ; and these animals may in their turn serve as food for 

 the predatory ones. Titanethes albus may be instanced as a link 

 between the outer animals and the predatory animals within, on 

 account of their frequency and mode of living. But it is difficult 

 to understand the mode of life of Stagobius Troglodytes ; or how 

 this slow and defenceless animal can escape being devoured by 

 the rapid, piratical Arachnidans, or find adequate support on 

 columns, for inhabiting which it is so manifestly constructed. We 

 are led in this respect to consider the antennae. Whatever signi- 

 fication we attach to those enigmatical organs, we must admit, that 

 they are organs of sense, in which view an animal having them 

 so much developed as Stagobius, must possess a great advantage 

 over its enemies, if these be only Arachnidans. Its cautious and 

 slow progress, and its timid reconnoitring demeanour, fully indi- 

 cate, that it is conscious of life being in perpetual danger, and that 

 it endeavours to the utmost to avoid that danger. Darkness, 

 which always favours the pursued more than the pursuer, comes 

 to its aid, especially on the uneven, excavated surface of the 

 columns. Nor is it difficult to suppose, that it procures sufficient 

 food, more so, perhaps, than is the case with many insects living 

 in the open air ; for, the stalactites can scarcely be more void 

 of vegetation, or present generally a more hopeless appearance, 

 as the abode of insects, than the spots on the confines of the snow- 

 line of the Alps, which continue uncovered only a few weeks in 

 summer ; or the ashes and lava at the foot of the crater of Vesu- 

 vius and /Etna ; or the naked sands, washed by perpetual spray 

 from the sea, on the cliffs at the extremity of Skagen. And yet, 

 these lofty Alp-regions are inhabited by not a few peculiar, wingless 

 insects ; the scanty manure, left on the sides of the volcanos by 

 the mules and horses of travellers, is sought after by a peculiar 

 Aphodius ; and the above-mentioned sandy spots are covered, 

 during the entire summer, by myriads of nests of Bledius are- 

 narius. 



