372 THE FROG-SHELL. 



course of writing the descriptions ; and I must here return many thanks to Mr. G. B. 

 Sowerby for his liberality in giving me access to his collection, in order to describe the 

 individual specimens from which the illustrations were taken. 



BELOW the Sea Trumpet lies another shell, which would hardly betaken for a Triton 

 until turned over, so as to show the whole of the contour. This is the WRINKLED or OLD 

 WOMAN TRITON, so called because the corrugated and rudely oval mouth, with its white 

 crumpled folds, is thought to bear some distant resemblance to the face of an old woman 

 surrounded with a close cap. The Wrinkled Triton is comparatively a small species, 

 as may be seen from the proportions preserved in the figure. 



BEHIND the larger figure is seen the TWISTED TRITON, represented in the act of crawl- 

 ing, and given, not so much to exhibit any peculiarity of its shell, which is hidden behind 

 that of the larger species, as to show the form of the animal, its large foot, and eyes 

 placed at the bases of the. tentacles. The operculum of this animal is small and leaf- 

 shaped, the nucleus being at one end. 



5PINED FROG-SHELL.- FROG-SHELL.- . BULL-FROG SHELI 



Raaella splnosa. Raoelta Rana. Ranella bufonla. 



As the spider-shells, which have been recently described, have received their popular 

 names from the distant resemblance which they bear to the arachnidian race, so the shells 

 upon the accompanying illustration derive their titles from a still more distant resem- 

 blance to the batrachians, and go popularly by the name of Frog and Toad Shells. Even 

 in the short space that has been given to the molluscs, the reader must have been 

 struck with the singular perceptive powers of conchologists, who discover analogies 

 and detect resemblances in creatures so dissimilar in shape and color, that few are 

 capable of appreciating them, even after they have been pointed out, or of precisely 

 comprehending the grounds on which the distinguishing names are given. 



The FROG-SHELL is the central and uppermost of the three species represented in the 

 illustration, and seems to have been gifted with its popular name on the same principle 

 that caused a well-known dramatic character to detect in a cloud an equal resemblance to 

 a whale and a camel. All the members of this genus possess two rows of ridges, 





