2/4 CRUSTACEA, ECHINODERMS, ETC. 



(Gonoplax). The former has the singular habit when 

 at rest of simulating the appearance of rounded 

 quartz pebbles. In addition to these may also be 

 seen the interesting Xantho florida and X. rivulosa, as 



Fig. 205. 



Stalked Barnacle (Lepas anatiferd). 



well as Dromia vulgaris, or "toad crab," so called 

 from its sluggish appearance. It is covered with a 

 kind of pile or hair. The fourth and fifth pairs of legs 

 are very short, and close-pressed against the carapace. 



