Crabs. Lobsters, Shrimps, Barnacles etc. 73 



body. The first point which will attract notice in these, is the curious 

 way in which they are covered with all sorts of foreign substances; 

 thus Pisa (Fig. 146) carries quite a forest of small algge and colonies 

 of animals (Polyzoa and Hydroid-polypes) on its back and legs; Inachus 

 (Fig. 145) carries about on its slender legs plants, sponges, and ascidians ; 

 in fact the more crabs we examine the greater is the variety of toilets 

 that we see. And what is their use? They afford the best possible 

 concealment from enemies and from prey. For all these objects have 

 not fastened themselves on the crabs, but have been artistically placed 

 there by the crab itself we dare hardly say intentionally but by 

 reason of an inherited instinct which impels the animal to disguise 

 itself in this way. All triangular Crabs are exceedingly slow in their 

 movements , and dressed up in this way they resemble most closely a 

 stone overgrown with sea-weed; especially as they have the habit of 

 remaining quite motionless when alarmed. The apparatus for affixing 

 these foreign bodies consists of a number of hooked bristles which are 

 distributed all over the shell ; there the crab deftly fastens with its claws 

 the alg;p and other ornaments. The Larger Spider-crab, Maja squinado 

 (Fig. 4^), covers its back with small stones and shells instead of with 

 sea-weed. 



Lambrus (Fig. 143} departs from this custom and depends more 

 upon its large and strong claws than upon concealment. 



Some of the Crabs with a square body have similar habits. Dorippe 

 lanata (Fig. 142) gets hold of any living or dead object within its reach, 

 holds it above its body with the claws of the two last pairs of legs, 

 and walks about thus concealed. Sea-cucumbers and ascidians, crabs and 

 starfishes, fishes' heads, bits of glass or wood, in fact anything and 

 everything which can serve as a shield, is annexed without further ado. 

 Naturally, when the desired shield happens to be a living animal, there 

 often ensue very laughable conflicts between the instinct-obeying crab 

 and its reluctant victim. 



Dromia, the Woolly-crab (Fig. 167), covers itself so completely with 

 an orange-coloured sponge (Suberites. 

 p. 55), or with a colony of compound 

 ascidians, that, if you look at the 

 animal from above only its legs are 

 visible. Here, too. the living coat, 

 which increases in size as fast as the 

 crab, is held on by means of the two 

 last pairs of legs. 



The crabs with a round body 



behave very differently, for they are T- ^ i 



, * , J1 Fig. 16 /. Dromia vulgar is covered 



extremely clean. Calappa, the Bash- with a sponge; i/ 2 nat size . 



ful-crab (Fig. 138), seeks protection by 



burying itself in the sand. With a few vigorous movements of its 

 large shovel-like legs it sinks itself up to the eyes in the sand, and 

 carefully surveys the country from this retreat. Ilia (Fig. 141) acts in 

 the same way. 



The most highly developed forms of this group are the Shore-crabs, 



