CONES, BASKET -SHELLS, AND OTHER 



MARINE SNAILS c:''' 



"One of the most abundant of mollusks," began the Professor, 

 " is the violet sea snail (Janthina), which spends its whole life float- 



ino 1 on the waters of the Atlantic and Pacific oceans. The shell 



& 



is very delicate, resembling in form some of the land snails, and has 

 but two colors, both being shades of violet, a deep color on the under 

 side, which is always turned upwards when the animal is in the water, 

 and a lighter shade on the upper side. So fragile is the shell that 

 it seems as if a breath could break it. The most interesting fact in 

 connection with this mollusk is the wonderful float, or " raft," which 

 is secreted by the foot, and to the under side of which the eggs are 

 attached. The latter are not all in the same condition; those nearest 

 the animal are more or less 

 fresh ; those in the middle 

 of the float contain embryos 

 and fully formed young, while 

 those on the outer end are 

 empty, the young having 



' . The violet sea snail, Janthina fragihs, with the ani- 



into the Water. 1 he mal and egg-float in their natural positions, a, float; 

 irp o-i-PO-flpinnq anrl mav b> eggs; c> gills ' or breathing organs; d, head with the 



are giegai us, ana nay tentacles. (Tryon.) 

 be found in countless numbers 



in various parts of the ocean. During a severe storm they are some- 

 times cast up on the beach in vast quantities, where they soon die 

 under the fierce rays of the sun, or else fall a prey to various species 

 of birds. 



" A handsome group of shells, which is related to Janthina, is the 

 genus Scala the ladder-shells or wentle traps. These snails are 

 found in all parts of the world, on rocky or sandy shores, below 

 the low-water mark, The shells are nearly always pure white, and 

 they receive their name of ladder-shells from the regular series of longi- 

 tudinal ribs which mark the whorls The large Chinese wentle trap, 

 Scala pretiosum, was once very highly prized, and most extravagant 

 prices were paid for specimens. It is recorded that on account of its 



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