Ch. n.] SWIPT-POOTBD CEABS. 25 



of Dermestes, and a little Corynsetes, cosmopolitan in its 

 habitat, and common nearly aU over the world. 



Among the coral-debris upon the beach were numerous 

 masses of various sizes, consisting of roUed Astraeas, Mad- 

 repores, &c. ; and mingled with them were fragments of 

 shells of a great many species of Conus, Cyprsea, Turbo, 

 Pinna, Hippopus, &c. ; but none of them entrte. Innu- 

 merable little hermits (Paguri and Cenobitse) occupied the 

 deserted shells of Naticse and Neritinse, and larger ones 

 those of good-sized Turbines ; but I saw no live shells upon 

 the beach, except a few insignificant ones, such as Litorinse 

 and Purpurse ; nor, though the water was bright and clear, and 

 I waded out as far as I could go, could I anywhere see traces 

 of Annelids or Echinoderms. The harder parts of the sand 

 were perforated with deep holes of various sizes, from which 

 emerged from time to time a wary and swift-footed crab 

 (Ocypoda), which scuttled nimbly down to the sea upon the 

 first sign of approaching footsteps, and appeared to be aware 

 of us at least at 50 yards distance. Nor was it easy to 

 capture a specimen, for while on the one hand they never 

 made the mistake of running away from the sea, on the 

 other hand, if cut off, they fled so quickly, and doubled so 

 nimbly, suddenly running the opposite way without the 

 clumsy. process of turning round, that they afforded great 

 amusement and not a little exercise and exertion. 



The sea in the neighbom-hood of the Pratas Island has a 

 very variegated appearance, from the alternations of bare 

 white sandy bottom, with patches of Ulva and Zostera, both 

 of which are very abundant. The Ulva is a very beautiful 

 reticulated species (Ulva reticulata, Forsk.), and the Zos- 

 tera leaves float about in aU directions and in all stages of 

 decay, generally hearing upon them minute dendritic poly- 



