176 NATURAL HISTORY OP OUR SHORES 



to weeds, sponges, or ascidians that are on the under side of 

 overhanging blocks of stone, or the roofs of little caverns, 

 and thus hangs, head downwards. In this position, and in 

 such localities, when it is densely covered with weeds, 

 which it attaches to its hooks, it is not easily discovered. 

 It is no doubt owing to this very effective concealment that 

 it is written of as " very rare." In the arrangement of the 

 hooked bristles there is regular system, and on each side 

 of a little groove that runs lengthwise on the rostrum or 

 " beak," they are set in a row, with their points facing 

 those on the opposite side, so as to hold a bunch of sea- 

 weed directly in front. This is the case with all the Lepto- 

 podiadce. 



In the photo (Fig. 81) an ache us in full decoration is 

 shown, just as it was taken, and the same specimen stripped 

 of his upholstery. 



Allied to the foregoing is the genus Inachus (Fig. 82). 

 These are larger bodied crabs, but with still the same 

 general outline (only broader). These have no hooks, but 

 have that peculiar " pottery " surface to the shell which 

 affords a good base for sponges, etc., with which they are 

 invariably covered. 



It is to this genus that the world's largest crab belongs 

 viz. the Inachus giganteus of Japan, which has a stretch 

 of legs of ten or twelve feet. 



The species on our shore are Inachus dorsettensis, Inachus 

 dorynchus, and Inachus leptochirus. These resemble each 

 other, except in points which could not be elucidated with- 

 out diagrams. The last-named can, however, be readily 

 identified by its having a little pearly tubercle on the 

 under side. All these are found at extreme low water, at 

 the base of rocks. 



The little " Nut Crabs," somewhat resemble these, except 

 in length of leg, for here the very extreme, shortness, is the 

 case, These belong to the family Leucosidce. They are 



