RANELLA. 



TESTA ovalis vel oblonga, depressiuscula vari- 

 cibus plus minusve obliquis, utroque latere 

 seriem longitudinalem efformantibus onusta. 

 Apertura subovata, basi canaliculata, superne 

 pier um que eanalifera. 



A VERY natural Genus which may be known at the first 

 glance, by the two lateral rows of varices and by the 

 general form, which in most species is such as to have 

 obtained for them the common name of Frogs, from 

 whence Ranella: but we must remark, that these rows of 

 varices are not always regular, and that there are some 

 species which approach Triton, in having the varices 

 rather more distant from each other than the length of 

 half a volution. With the exception, however, of the 

 Tritones, we believe there is no danger of the Ranella 

 being confounded with any other Genus, for it is easily 

 distinguished from Murex, which has at least three rows 

 of varices to each volution. It does not appear to us to 

 be related to Struthiolaria, though Lamarck seems to 

 consider it as in some respects intermediate between 

 Struthiolaria and Murex. 



We must not omit to notice a singular opinion ad- 

 vanced by Lamarck, that " on the addition of every new 

 piece which the growth of the animal obliges it to make 

 to its shell ; this animal comes out and exposes itself for 

 the entire length of an half volution, and thus remains 

 stationary until the new half volution is formed :" which 

 fact,'' he says, is indicated by an examination of the 

 shell, and evidenced by the varices being constantly dis- 

 posed on the two opposite sides." Upon this we shall, 



