MOLLUSCS. 



349 



about, exposed to the full rays of the sun. They are littoral annuals, occurring most 

 numerously near or just below low-water mark. The colors of the shells are lirinht, 

 or are laid on in pretty and striking jiatterns, while the animals are, if 

 possible, even more beautiful than the shells. Some of the species are 

 among the conchological rarities, and for tliem, in times 

 ](ast, enormous prices have been jjaid. The rarest species 

 (or at least the highest priced ones) are C. guttata and C. 

 princeps. Certain species have always been highly prized 

 by savage races, and Vypnaa moneta, the money cowry, 

 passes, or used to pass, as the current medium of exchange 

 among some of the African tribes. It is a native of tlie 

 Pacific Ocean, and is brouglit in large numbers to Eng- 

 land and thence shijjped to Africa to be used in barter. 



Among the sub-genera may be mentioned IVivia, Lu- 

 ponia, and Aricia, C. moneta being a reiiresentative of 

 the latter. Trivia strays into northern waters, one species being found 

 in European seas, while another is found in California. The sub-genus 

 Luponia is also represented by two sjiecies in the latter region. All 

 the species of Cyprma are carnivorous, and they eat living or dead food. 



The species of Ovuluni are to be recognized by their elongate shell, which, in some 

 forms, is greatly drawn out at the extrenuties, as in the weaver's-shuttle shell, 0. volva, 

 from the Phili])pines. These shells are not so prettily marked as the cowries are, but 



Fig. 453.— Trii'ia 

 catifornica. 



FlG.454.— Tnt) 

 curopcEa. 



Flc 455. — Urillum tolru, wiiavcr's sliuttle shell. 



ar^ usually more or less unicolored, and the color sometimes corresponds to that of 

 the surroundings, and the Floridian species, Ovuhim tmipKcatum., is said to be yellow 

 or purple according to the color of the gorgonid corals on which it dwells, and on 

 which it is supposed to feed. 



The Steombidje receive the common name, wing slu'lls, on account of the broad 

 wing-like exj)ansion of the outer li]i in some of the species. Other 

 conmion names are apjslied to some of the members of the family. 

 The animals are among the most active of the molluscs. The long 

 and muscular foot is divided into two halves, adapting it for pro- 

 gression by a sei-ies of leaps instead of the ordinary creeping motion. 

 Tlie operculum is also an aid in locomotion ; it is claw-shaped and 

 toothed on the outer edge, and these serrations are used to obtain 

 a foothold. Then the foot is straightened by a violent muscular 

 action, and the animal jumps forward. The other p.arts are 

 ecjually well developed, and seem to demand for these animals 

 a place near the toj) of the gasteropod series. The eyes are large 

 and placed at the extremities of the thick stalks, while the ten- 

 tacles are long and slender, the tentacles and eye-stalks being united for a portion of 

 their length. The muzzle is long and extensible. The strombs are carnivorous and 



FiQ. 456. — StTombus 

 pugllis. 



