CRUSTACEANS So lately as ten or twelve years ago the Crustacea of this county were still suffering from a kind of conspiracy of silence. A few Entomostraca, noted as occurring in pools and ditches round London, might be presumed to inhabit this part as well as others of that great circumference. One important species is recorded by Baird, on the authority of E. Doubleday, Esq., as having been taken ' near Epping.' l On the not improbable assumption that this was found within the borders of the county, Essex may include in its fauna the beautiful non-crustaceous crustacean, Cbiro- cephalus diaphanus, Prevost. This is a creature that collectors may accuse of caprice. Its appearances are fitful. The secret lies in its adaptation to shallow patches of water, liable to complete desiccation. Though it cannot itself survive the vanishing of its native pool, its eggs will rest contentedly in an expanse of dried mud or meadow, till some miniature deluge, instead of destroying them, restores them to a watery world. In this they speedily hatch, pass through their larval stages, and in the adult form are distinguished by their glassy length, the constant movement of their leaf-like limbs, and by the negative character of having no carapace. The graceful slenderness of this species is in strange contrast to the clumsy, sullen-looking figure of the hard and hairy-coated Dromia, a rare crab, and the only one that Adam White in his Popular History of British Crustacea^ assigns to Essex. Unfortunately White seems to have been less trustworthy as a geographer than as a carcinologist, for he says that the Dromia vu/garis was ' first recorded as British by Dr. Gray, who obtained a specimen in Billingsgate market, amongst oysters from Whitstable in Essex, in 1825.'* It is possible that, using a very small map, he found the name of Whitstable stretching all across the mouth of the Thames, and so fell into the confusion of transferring the place from the southern bank of the river to the northern. For vagueness and inadequacy in the past science has lately been making ample amends, and when a thorough investigation of its Mala- costraca and salt water Entomostraca has been completed, the county may find that its marine Crustacea are as diversified and interesting as those of its inland waters have been already proved to be. Of the Brachyura or short-tailed crabs, Mr. Edward Lovett has recently published the following records. After mentioning that ' the spider crabs of the genera Stenorhynchus and Inachus are very delicate in structure, and occur in deep water in the western parts of the Channel,' he continues, ' Stenorhynchus rostratus is common in the Thames estuary. A more robust form Hyas araneus (and its near relative H. coarctatus] are 1 British Entomostraca, Ray Soc. p. 54 (1850). 2 Popular Hist. Brit. Crust, p. 68 (1857). 204
