
MOLLUSCS, VERMES AND HYDROZOA 

They are for sale in the Oriental quarters of some of the Pacific 
cities, and are collected in the rice fields near Yokahama and there sold 
for a few cents a quart. They are ovoviviparous, very hardy, most tenacious 
of life, and when not buried under the pebbles, the most indefatiguous 
“workers” of any of the snails bred as aquarium scavengers. In the 
author’s vicinity they may be had of several breeders who have given them 
preference to the other three desirable species. ‘he shell is similar to 
V. viviparus but darker in color, lacking the bright color bands, and has 
a distinct keel in the centre of the body whorl, extending part-way on the 
next following. They grow to a diameter of 2 inches and over, and their 
almost entirely black color makes them conspicuous inhabitants of the 
aquarium. They are harmless to the plants, ravenous feeders on alge and 
offal, never at rest and constantly moving over the glass of the aquarium, 
or feeding on the parasitic alge on the water plants and on the humus under 
the pebbles. The young, when they leave the female, are 34 inch in 
diameter, having a horn-colored, very markedly keeled shell. “The Chinese 
species of the same genus is /’. ste/maphora, for which the above has been 
mistaken; but this snail has not been introduced into the United States. 
The Japanese snail will cross with the Potomac snail, the mixed breed 
more resembling the latter, as it does not have the keeled shell of the 
Japanese snail. 
For the aquarium intended and equipped for fishes, these four species 
are particularly recommended. Nearly all the others mentioned are not 
desirable and should be introduced only when the approved species 
cannot be obtained. More than one species is also advisable, as they all 
vary somewhat in their preference of diet. 
Snail, Breepinc. A “snail farm” in which the desirable aquarium 
snails may be bred is best arranged in a large jar in which there is a 
luxuriant growth of aquatic plants rooted in clean soil and covered with a 
thin layer of sand. No fishes or insects should be introduced, as they prey 
upon the young snails when first liberated from the gelatinous capsules of the 
oviparous species and the newly born young of the ovoviviparous genera. 
Feeding with any of the starchy fish foods should be occasionally done, as 
the young snails thrive better than when entirely dependent upon alge 
and decaying vegetation; but this should not be done in excess that the 
snails may not feed too considerably upon this supply and thereafter become 
less effectual scavengers. Excessive feeding would also contaminate the 
water and cause the death of the snails. 
When many snails are kept in an aquarium, it is advisable to place a 
few pieces of gypsum or of plaster of paris, about the size of a large pea, in 
the tank three or four times a year. These gradually dissolve and 
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