1849.] SHARPE ON THE GENUS NERIN^EA. 109 



N. pulchella, Thurm. Porrentr. 17, is a Cerithium according to 

 Voltz and Bronn, Jahrb. 1836, p. 566. 



iV^. quinquecincta, Goldf. t. 176. f. 2 ; probably a Cerithiumi 



N. tricincta, Goldf. t. 176. f. 1, is a Cerithium. 



N. turritella, Goldf. t. 176. f. 5, is also Si Cerithium : these two 

 last bave only a fold on the columella, which may be seen in C. gi- 

 C. cornucopicB, &c. continued throughout the spire. 



The fossil remains of NerincBa are usually found in company with 

 corals, Ostrsese, Pectens, and other shells supposed to have been natives 

 of shallow seas ; and rarely near many Terebratulse or Ammonites. 

 It is probable, therefore, that they were littoral animals. They are 

 most common in beds of limestone, are seldom seen in sandstones, 

 and still more rarely in clays. 



In England we have in the different beds of oolite many species of 

 Nerincea, but only one, N. Goodhallii, which attains a considerable 

 size ; and there are only one or two very small species known in the 

 cretaceous system. 



In the North of Germany, according to Roemer, the oohtic series 

 furnishes several species of Nerincea of middling size ; but only one 

 species is known in the greensand, and none in the chalk. 



In the South of Germany, Voltz and Goldfuss have published 

 several large and small species both from the oolitic and the creta- 

 ceous systems. 



In France the oolitic species of Nerincea are large and numerous, 

 but they have been but imperfectly described. M. D'Orbigny's 

 * Paleontologie Fran9aise' gives us full information of the distribution 

 of the cretaceous species. There have been eleven species found in 

 the subcretaceous beds, of which the six from the basin of Paris are 

 small or of middling size, while all the five found in the South of 

 France are very large : the fifteen species found in the Craie chloritee 

 are all from the South of France, only one reaching as far north as 

 the Loire ; some of these are large, but they do not equal in average 

 size the subcretaceous species from the same districts. None have 

 been found in France in the upper chalk. 



In Portugal I met with no NerincecE in beds of the oolitic period ; 

 but these beds appear to have been deposited in deep seas ; and more- 

 over, my examination of them was too slight to found anything on 

 this merely negative evidence. In the beds classed as subcretaceous 

 the species of Nerincea are numerous, and many reach a very large 

 size. From the hippurite limestone, which is of the age of our 

 chalk, and which I examined very thoroughly, I have three species, 

 the largest of which is only of moderate size. 



It thus appears that the period most favourable to the development 

 of Nerincece was that of the oolites in the North, and that of the 

 greensand in the South of Europe. Comparing together the species 

 found in different formations of any one country, we find the species 

 of the older formation more numerous and on the average larger than 

 those of the more modern formation. 



But on comparing the Nerincece found in the same formations in 



