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by various traits of artful and calculating utilization of the si- 

 tuation on the part of these little creatures. Hermit-crabs come 

 next in rank to the short- tailed crabs, to which we now turn 

 our attention. 



In the hermit-crabs we found a retrograde development of 

 the hinder part of the body in consequence of the long conti- 

 nued habit of living in shells. In the short- tailed crabs this 

 retrograde formation has gone much further, but in favour of 

 another principle, that is, of fredom of movement. Here we see 

 the larger portion of the body, which in the lobster we called 

 the tail, reduced to a small round or three-cornered plate, which 

 is doubled under, the edge lying close to where the legs begin. 

 In the female this plate is hollowed like a dish for the reception 

 of the eggs; in the male it is simply a pointed three-cornered 

 plate stuck fast into the niche destined for its reception. But 

 the forepart of the body is developed crosswise and is generally 

 of an oblong or square shape. The wellknown purse- crab may 

 serve as a type of this group ; it is familiar to most people 

 from collections, engravings or personal observations. 



We will next draw attention to the crabs with a three-cor- 

 nered head-and-breast plate, of which the species Pisa, Lissa, 

 Maja, Inachus, and Stenorhynchus are the most interesting. 

 What will most strike the observer in these animals is their 

 being covered by all kinds of foreign substances. One carries 

 on its back and legs a complete forest of algae and moss-ani- 

 mals; another glories in a strange decoration composed of the 

 stems of Hydroid polyps, which . grouped in a bunch , adorn 

 the spikes of his forehead ; others, for example the Inachus 

 drag about , clinging to their long thin legs , plants , spon- 

 ges and ascidiae ; in short , the more crabs we examine 

 the greater variety of toilettes shall we see: and their use ? 

 They are the best possible means of concealing the animal 

 from its enemies and from its prey. All these things have not 

 voluntarily fastened themselves to the crab , but have been 

 artistically placed there by itself, with wehardly dare say - 

 conscious intention, but certainly with an hereditary instinct 

 that impels the animal thus to disguise itself; and the mask, 

 in many cases, is so successful, that it even deceives the knowing 

 eyes of men. All these three-cornered crabs are extremely 

 sedentary, and, as they remain motionless when alarmed, exact- 

 ly resemble stones overgrown with moss or sea-weed. Their 

 apparatus for fastening these foreign bodies in their backs 

 consists in a number of hooked bristles, arranged according 



