MOLLUSCS, VERMES AND HYDROZOA 



Best Aquarium Snails. Experienced aquariists avail themselves 

 of but four species as aquarium scavengers. These are the Planorbes, 

 usually P. trivolvis, the larger common species, popularly known in the 

 author's section of the country as the "Ram's horn" or "flat Schuylkill 

 snail;" Viviparus viviparus or "Potomac snail;" Lymnaa auricularia or 

 "Transparent African snail;" and Viviparus malleatus or "Japanese snail." 

 The first two have been already described, the latter two will now be 

 mentioned. 



L. auricularia. Fig. 178, is native to the water systems of the Medi- 

 terranean and some other parts of Europe. It is a beautiful snail having 

 a peculiar earshaped shell with a broad body whorl and the others flattened 

 and rapidly diminishing, 

 and a depressed spire. The 

 shell is of a nearly trans- 

 parent light horn-color, 

 through which the darker 

 color and the brown and 

 black spots of the body 



plainly show. It has broad "°- '^^^ transparent African snail, Lymn^a auricularia. 



and flat conical tentacles, small dark eyes and a broad foot, paler on the 

 under side. It feeds entirely on algae, decaying vegetation and ofFal, never 

 attacking growing plants. It is active in habit, never comes entirely above 

 the surface of the water, thrives in the aquarium and is one of its most 

 interesting inmates. It is not as tenacious of life as the first two named, 

 but is prolific and reaches a maximum length of 1 1/^ inches. Its eggs are 

 deposited in long vermiform gelatinous masses on the stems and under 

 the floating leaves of plants and on the glass of aquaria; which hatch in 

 12 to 20 days, the tiny snails being almost invisible in their transparent 

 shells. This snail is exotic but is extensively bred in the Eastern and 

 Middle States; may sometimes be had of dealers, but is usually obtained 



by exchange or purchase among 

 aquarium fanciers. 



V. malleatus, the Japanese 

 snail. Fig. 179, has now become 

 naturalized at San Jose, Califor- 

 nia, in a little valley at the foot 

 of Mount Hamilton. It is an 

 edible snail,known to the Chinese 

 as "Tsen law," which was either 

 planted or accidentally intro- 

 duced by the Chinese and 

 Japanese of the neighborhood. 



FIG. 179. Japanese snail. Vimparus malleatus. 

 Nearly adult and younger shell, showing keel. 



238 



