156 



MEDITEKRANEAN PROVINCE. 



ralists on the coasts of Greece, one-third are British ; 

 and of the three species of Stomatopods we have 

 two — Squilla mantis and Desmarestii. 



The Mediterranean Crustacea are interesting in 

 another point of view : the mineral composition of 

 the external crusts of these animals favours their 

 preservation ; hence their remains are abundant in 

 the old sea-beds of this area, and enable us to com- 

 pare the relations of the present fauna to a former 

 one, as readily as by the aid of fossil shells. Geo- 

 logical changes, and the influence they have exer- 

 cised in the breaking-up of former zoological 

 regions, or continuity of given forms, seem the sim- 

 plest resource by which to explain the present 

 apparent isolation of certain species. 



The Nephro'ps Norwegians has its numerical 

 maximum in, and is a good characteristic Crustacean 

 for, the Scandinavian region, but it occurs abun- 

 dantly in Dublin Bay ; it has not, however, accord- 

 ing to Mr. W. Thompson, a general distribution — 

 such as west and south, even throughout the Irish 

 seas. We may feel sure, from its excellence as an 

 edible species, that it has not been overlooked by 

 fishermen, whilst its size, form, and proportions 

 make it the most elegant Crustacean we have — a 

 prize which no naturalist would overlook ; yet, 

 strange to say, it has not been recorded from the 

 western coasts of France, nor do we meet with it 

 till we reach the Mediterranean. It seems to be 

 abundant in the Adriatic, in which sea it may be 



