96 Proceechnijs. 



habits, never become encrusted with sponges, zoophytes, &c., 

 as do some others that we shall notice presently. The proverb 

 that "a rolling stone gathers no moss " is wonderfully well 

 verified in their case. 



As a contrast to this beautiful and lively family we will 

 now turn to one of a directly opposite nature, namely, the 

 Maiadm, embracing three of the largest genera to be found 

 anywhere. The genus Pisa contains two species, P. Utraodon 

 and Gibbsii, both of which are liable to the growth of zoo- 

 phytes. Algae, &c. ; but the latter, owing to its hairy carapace, 

 is particularly so liable, being often found perfectly hidden 

 by a sponge growing upon its back. No doubt thousands are 

 killed by these sponges, for I once found one (dredged up) 

 which had only its mouth-organs, eyes, and one leg left free, 

 so closely had its parasitical sponge insinuated itself, and yet 

 it was alive so far. I have obtained a very fair series of 

 growths on the backs of these remarkably sluggish animals. 



Another member of this family, Maia squinado, is covered 

 with spines, which are generally to be noticed in old speci- 

 mens as having been rubbed down. This is owing to the 

 animal's habit of living in rock-crevices, into which he forces 

 himself, to the destruction of his spiny armour. This species, 

 which grows as large as a cocoa-nut, is eaten in the Channel 

 Islands, where it is much esteemed, and cheap withal. 



Closely allied to these genera are the beautiful little Spider 

 Crabs, Stenorhi/nchiis, Achaus, and Jtiachus. Of these the 

 rarest is Achmus Cranchii, a crustacean not much bigger than 

 and very like our long-legged Garden Spider. This curious 

 little species is often covered with bits of Algae, giving him a 

 ragged and untidy appearance. Stenorhynchus longirostris is a 

 graceful species, having a tapering body about the size of a 

 small nut, and delicate legs covering a space of from six to 

 eight inches in many instances. These are rather deep-water 

 species, and seem to be a favourite article of food for various 

 fishes. 



Going from a species of delicate and fragile structure 

 living in the quiet depths of the sea to one of massive form 

 inhabiting the shore about half-tide mark, where the roaring 



