NOTES ON CRUSTACEANS. 



dedly gregarious, for I invariably find several in one pool, however small 

 that may be. They seem to prefer the dark overhanging rocks containing 

 deep muddy holes, and I have counted as many as eleven and thirteen 

 in such a spot, when the pool has been no larger than an ordinary table. 



W seems to incline to the idea that the fragments are first entangled 

 in the hairs, take root, and gradually extend into the shell: now to me 

 this appears a scarcely feasible notion, as it is generally held that these 

 forms of life (Algce and Zoophytes) must be regularly developed from spores 

 and ovules. How then can a torn fragment take root and flourish? 

 Those individuals of the Crab kind that have come under my notice, 

 and they have been not a few, have given the preference to Algce of a 

 reddish brown colour, portions of which were nipped off and laid on the back 

 and about the head, a careful examination of large individuals would also 

 shew numerous minute growths springing up. I was much amused at the 

 appearance of a fine large Ilyas, which was stalking along, with all the 

 majesty which borrowed plumes often produce. It was seen in a large 

 deep pool, round the edge of which abrupt rocks stood out, affording a 

 shelter for some very fine tufts of Delesseria sanguinea; well, this indi- 

 vidual had established himself amongst the Delesseria, but noticing, no 

 doubt, that the colours of his shell was an unpleasing contrast to the 

 handsome weed, he proceeded to array himself with the desired covering; 

 little bits, the tips of the leaves, were accordingly detached and stuck upon 

 the carapace in an extremely irregular manner, giving the crab a most 

 ludicrous appearance; and as I moved to the pool to get a good view, 

 it merely stalked leisurely along, evidently quite safe. It is next to im- 

 possible for this delicate plant to grow from such fragments as here 

 described, the tips of leaves. 



Now having shewn that the covering is in certain cases mechanically 

 attached, I will endeavour to prove that it is a regular work which the 

 crab performs. My first acquaintance with Hyas was a small specimen 

 found during one of my early searchings on the rocks. This, with the 

 other captures, was put into an aquarium, but in four or five days I 

 missed it, and doubted not that like numerous other animals it was dead, 

 and therefore commenced a search, and soon found the remains, which I 

 immediately removed, and instituted a further search to see that nothing 

 else had shared the same fate, when lo! another Hyas was there, flapping 

 away with his little brushes, no doubt wondering who I was that thus 

 invaded his domains: now this completely nonplused me, as certain was I 

 that only one had been put into the trough. Being young on the subject 

 of aquaria keeping, I did not at first alight upon the idea that the 

 supposed dead body was merely the cast-off shell; but as this slowly 

 gained possession of me, the luxuriant growth of Algce upon the newly- 



