COKALS AND COITAL MAKERS. 9 



().; figure 3, Halocampa chrysa?ithcUum G. Most of these sand- 

 dwellers bury themselves like the Halocampa, and often hide 

 all the disk but the mouth. The Edwardsia is peculiar in 

 having, above the hollow bladder-like basal portion, a firm 

 opaque exterior to the body, making for it a kind of case or 

 jacket, into which the upper extremity, which is soft and 

 delicate in texture, may be retracted. I'he thickening of the 



epidermis in this middle portion is produced through the 

 entanghng of disintegrated cells and minute foreign particles, 

 sometimes in part spores of Confervae, by means of the mucus 

 of the surface ; and if the layer is removed, as it may be, the 

 skin will again become covered. This species, like others of 

 the genus, Uves buried to its neck in the sand, that is, with the 

 soft upper extremity protruding. If disturbed, the head is 

 suddenly drawn in, together with more or less of the following 

 jacketed part of the body. 



