FRONT-GILLED GROUP 



3349 



are armed with numerous long spines upon the ridges; M. tenuispina from the Indian 

 Ocean, Philippine islands, and neighboring localities, being a striking example. In 

 the section Chicoreus the shells are strong, with three beautifully branched ridges, 

 and the canal shorter than in the preceding group; M. ramosus, a large and abund- 

 ant species from the Red Sea, Indian Ocean, Polynesia, etc., and the beautiful M* 

 palma-rosce, from the Philippines, being examples. 

 The species of Miiricantha are like Chicoreus in 

 form, but with numerous varices. The west 

 coast of tropical America and West Africa pro- 

 duce some of the largest and handsomest species. 

 Of all the group, perhaps none surpass in beauty 

 of construction some of the forms of Pteronotus; 

 M. lobbeckei from the China Sea, which is of a 

 uniform delicate rose-pink tint, and ornamented 

 with elegant fluted frill-like varices, being pre- 

 eminently beautiful. There are several other 

 groups containing a number of species of con- 

 siderable interest, which cannot be further re- 

 ferred to in this account. Some mention, how- 

 ever, must be made of the dye which can be 

 extracted from the animals of this family. Species 

 of Murex and probably of Purpura a genus re- 

 ferred to subsequently were both employed in 

 ancient times in the manufacture of the Tyrian 



purple. The dye was obtained from a white vein at the upper part of the neck of 

 the mollusk. When first extracted, it is of the color and consistency of cream, but 

 subsequently changes, on exposure to light, to the deep purple tint. The common 

 British Purpura lapillus affords similar dye. Its scarcity and the use of cochineal, 

 and other dyes, render it valueless as a commercial product. Murex erinaceus, the 

 only British species, is common on oyster beds, to which it is destructive. All the 

 forms yet referred to have a somewhat roundish or ovate operculum, with the 

 nucleus terminal or subterminal, whereas in those which follow 

 (Purpurince) it is lateral. All the members of the genus Purpura 

 are furnished with strong, heavy shells, suitable for protecting the 

 inhabitants from the rough usage of the sea upon the rocky shores 

 EGG CAPSULES OF ^y mos tly inhabit. They range from the Arctic to the Antarctic 

 Purpura lapillus. regions, the handsomest species coming from tropical seas. The 

 fry of several species are pelagic, and swim at the surface of the 

 water. Like the murices, these mollusks are devourers of Bivalves. The annexed 

 illustration represents the egg capsules of the common British P. lapillus. The 

 animal and shell of Acanthina are similar to those of Purpura, but the outer lip of 

 the aperture is furnished at the anterior end with a more or less prolonged conical 

 tooth or prong. Rapana, Concholepas, and Sistrum are other nearly-allied ' forms. 

 The members of the family Coralliophilidce resemble the purpuras, but are charac- 

 terized by the want of a radula, and their singular mode of life, dwelling either in 



ANIMAL OF Murex. b. Gill; b' '. Os- 

 phradium or olfactory organ ; p. 

 Purple gland. 



