252 



SOME NOTES OF THE STALK-EYED CRUS- 

 TACEA OF THE BRITISH COASTS AND 

 REFERENCES TO ESSEX FORMS. 



Ahstyact on an Address delivered by Mr. Edward Lovett, at a 

 Meeting of the Chtb on February 14th, 7900. 



The Stalk-eyed (Decapoda or " ten-legged" Crustacea) are 

 divided into three groups, viz., the Brachyura or true Crabs, 

 the Macroura or true Lobsters, Shrimps, and Prawns, and the 

 Anomoura, embracing representatives of each of the former as 

 illustrated by the Stone-Crab Lithodes and the Lobster-like 

 Galaihea for example ; as also the Hermit-Crabs. One peculiar 

 characteristic, however, is that the fifth pair of legs are rudi- 

 mentary, and are, in fact, merely brushes, and are so used 

 by the animals in several instances. 



Of the Brachyura the best known species, and in most cases 

 the only popularly known species, are the Edible Crab, Cancer 

 pagurus, and the Shore Crab, Carcinns manas ; the majority of 

 the other British forms being seldom seen near the high-water 

 mark. 



The Spider Crabs of the genera Stenorhyncus and Inachus 

 are very delicate in structure, and occur in deep water in the 

 western parts of the Channel ; Stenorhi/Jicns rostratus is 

 common in the Thames Estuary ^and the Colne Estuar\\ Ed. J 

 A more robust form Hyas araneus (and its near relative H. 

 coardatiis) are the typical Essex " Spiders," as the members of 

 the genus are always found on a sandy or muddy bottom, to 

 which the colour of the crabs almost invariably corresponds. 



Another robust " Spider " form is Pisa gibbsii. This 

 species has its carapace covered with a dense mass of short fine 

 spines, forming a sort of " pile." Thus by catching and 

 entangling bits of Algai, spores of sponges, &c., it acquires a 

 perfect growth of such plants, so that the animal is thereby pro- 

 tected from its enemies, the fishes, which although" ready to eat 

 any Crustaceans are averse to sponges and like growths. 



Curiously enough this very protection sometimes brings 

 about the destruction of the Crab, for the sponge growths 

 gradually cover the whole animal until its death is brought 

 about. [Specimens were exhibited to illustrate this._ 



