316 THE SPINDLE, OR DISTAFF SHELL. 



THE FROG-SHELL 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, technically 

 called "varices," upon the shell, one row being placed on each side. There are about fifty 

 species of Ranella, spread over all the warm seas. Lake the preceding shells, they prefer the 

 shallow to the deep waters, and may be found at almost all depths from the bare rocks left 

 waterless by the receding tide, to a depth of eighteen or twenty fathoms. 



The BULL-FROG SHELL has a roughly tuberculated surface, with deep hollows and bold 

 ridges of thick shelly substance, together with projecting horns on either side. The color of 

 this shell is extremely variable. In the handsomest specimens the ground color is creamy 

 white, largely mottled with bold tints of deepest brown and purest white. But in many 

 instances the entire shell is of a very pale tone, yellow predominating, and the brown 

 entirely subservient, and presenting the same contrast to the full-colored shell as the albino to 

 the negro. 



The SPINED FROG-SHELL derives its name from the sharp and rather long spines or pro- 

 jections with which it is furnished. None of these shells are of very great size, their average 

 length being about two inches. 



A VERT pretty shell is termed indifferently the LITTLE FIG, or LITTLE PEAR SHELL 

 (Pyrula ficus], because its general outline is thought sufficiently pear or fig-like to warrant 

 the application of the name. Both scientific names refer to this far-fetched resemblance, 

 pyrula signifying a little pear, and ficus meaning a fig. 



The foot of the Pyrula is abruptly cut off, or truncated in front, and modified so as to 

 form a short horn or partial crescent at each side. 



Nearly forty species of Pear-shell are known to conchologists, and are spread over the 

 warmer seas of the world, living in moderately deep water, varying from sixteen to thirty-five 

 fathoms of depth. 



This is a thin and delicate shell, the large expanded lip being especially so, and, 

 in consequence, is very light when the inmate has been removed. The color is very pale 

 yellow, with brown and white arranged in wavy mottlings. Its average length is about four 

 inches. 



The delicate thinness of the shell is not, however, a character common to the entire 

 genus, for another species, the BAT-LIKE PEAR-SHELL (Pyrula carndria), is quite as remark- 

 able in the opposite direction, its shell being peculiarly large and ponderously constructed. 

 This shell is found in the Indian Ocean, and its general color is dark bay. In all these 

 shells, however, the long canal which projects from the front of the shell is always open, not 

 being filled up witli solid matter as the animal increases in age ; and the columella, or pillar 

 of shelly substance, which runs up the centre of the whorls, like the solid centre of a screw, is 

 always smooth. 



A LARGE and boldly mottled shell, popularly known by the really appropriate name of 

 TULIP WHELK, bears in its rich and variegated coloring some analogy to that of the flower 

 from which it derives its name ; while the general shape is sufficiently like that of the whelk 

 to warrant its use, even though the two shells belong to different families. The generic name 

 of this shell is derived from a Latin word signifying a band, and is given to it on account of 

 the boldly banded stripes in which the colors are disposed. As in the last-mentioned genus, 

 the canal, though not so elongated, is always kept open. 



Comparatively few living species of Tulip-shells are known to conchologists, sixteen or 

 seventeen being their utmost limit. These shells inhabit the warmer seas, and some of them 

 attain a great size, such as the GREAT TULIP-SHELL, which sometimes reaches a length of 

 nearly two feet. 



BEFORE mentioning our last example of the Muricidse, we have to pay attention to the 

 SPINDLE, or DISTAFF SHELL (f^usus coins}, so called in allusion to its form. Its scientific 



