534 



LAND ANIMALS 



notable length, often set thickly with tactile hairs. The locustids of 

 caves have remarkably long antennae; Phalangopsis angulata, with a 

 body length of only 9 mm., has antennae 48 mm. long. 22 Many cave 

 beetles, spiders, and mites have very long legs (Fig. 135). Other 

 beetles bear tactile hairs scattered over the whole body (Fig. 135). 

 The cave beetle, Antisphodrus navarricus, which is indifferent to light, 



Fig. 135.— Cave beetles from caves in Herzegowina. Left, Anthroerpon apjelbecki; 

 right, Scotophnutes arenstorffianus. After Absolon. 



is extremely sensitive to slight air currents. 23 Cave crustaceans also 

 have notably elongated antennae. In Stygodytes (Fig. 133) they are 

 longer than the body, and in the cave Cambarus they are longer than 

 in the surface forms of the same genus. 24 



The organs of chemical sense are also more highly developed in 

 many cave animals than in their relatives above ground. The "sense 

 bulbs" of the cave isopod Asellus cavaticus are larger than in the com- 

 mon Asellus and have been shown to have greater sensitivity. 25 The 

 cave isopod, Caecidotea, is much more sensitive to mechanical stimula- 

 tion than is its epigeal relative Asellus communis. It is less sensitive to 



