SPINED FROG-SHELL. Raw-lla svinosa. 



FliOG-JjHKLL. Hanella RMM. 



BULL-FROG SHELL. Ranclla bufonia 



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 he taken 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 crawling, 

 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. 



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 resemblance 

 to the batrachians, and go popularly by the name of Frog or 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 iii shape and colour, 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, 



