170 



MEDITERRANEAN PROVINCE. 



152, in which is included, therefore, the number 

 representing the proportion of forms indicative of 

 the province. 



Of the north Spanish Testacea, which have been 

 already noticed (pp. 108-9) as characteristically 

 northern, some few do not seem to range much 

 farther south, such as Lacuna puteolus, Littorina 

 rudis, L. littorea, and Purpura lapillus ; but others, 

 such as Velutina laevigata, Trochus lumidus, Mactra 

 subtruncata, Tapes, and Pecten, are Genoese ; and 

 what is somewhat curious, Patella pellucida and 

 Trochus cinerarius occur on the west coast of Africa 

 (Marocco). 



Of the short list of southern shells which enter 

 into the north Spanish fauna, some do not extend 

 equally far north in the Mediterranean. 



The bearing of Mr. Jeffreys' researches in the 

 Gulf of Genoa on the question of marine zoological 

 provinces, will be considered in the sequel. 



Of Piedmontese Bivalves, as many as eighty are 

 British; of the Univalves, about ninety. 



" It is remarkable," says Mr. Jeffreys, " that ex- 

 amples of the same species are smaller than those 

 found in the British seas. Tellina balaustina, Jef- 

 freysia diaphana, and Eissoa pulclierrima are in- 

 stances of this." 



This diminution in size, which is to be observed 

 with respect to many other species, such as Corbula 

 nucleus, when traced from north to south, is the 

 more remarkable because the converse does not take 



