THE 



AQUARIUM 



On Freshwater Snails. 



Plate I. 



W. A. POYSER. Hammond. Incliana. 



WHILE much space has been 

 devoted to snails by authors 

 of books on aquaria, little effort is made 

 by the average aquarist to secure more 

 than a few species. Quite a number 

 of interesting species are suitable for 

 the household tank, provided they are 

 selected with discretion. In the opinion 

 of the writer the necessity of snails in 

 the aquarium is somewhat over-empha- 

 sized, and that they should be kept as 

 much for their interest as for the 

 practical benefit as scavengers. I have 

 yet to see an aquarium that did not 

 require frequent cleaning regardless of 

 the number of snails. Some species of 

 fish devour more Algae than snails. I 

 have in mind the red-bellied dace. When 

 I clean the glass of my tanks, the dace 

 gorge themselves. I use a safety razor 

 blade. It is unnecessary to remove the 

 Algae with a syphon. 



Judgment must be used in selecting 

 an assortment, lest the destruction of 

 plants results. The misnamed Singapore 

 snail is a gross plant eater and must be 

 kept alone. The Niagara snail, Limnaea 

 stagnalis, while a vigorous vegetarian, 

 may be kept in the tank with impvmity 

 if one is satisfied with one or two 

 individuals. This is one of the most 

 attractive of the more common species. 

 It spawns freely, but should be bred in 

 a separate tank if it is desired to raise 

 the young. The Limnaeas are air- 

 breathers, having a lung, hence come to 

 the surface to breathe. The genus is 

 widely distributed all over the world 

 from the arctic regions to the tropics. 

 The young animals of this genrs breathe 

 air through the water, but later develop 

 the characteristics of the matvire snails 

 ard breathe the air direct. Water- 

 breathers have gills which take oxygen 

 direct from the water. 



The AmpiiUarias come principally 

 from the tropics. Usually the Singapore 

 or Four-horned snail (Ampiillaria gigas) 

 is the only one readily obtainable. They 

 are exceedingly tenacious of life and 

 have been known to live for several 

 years away from water. Ampullaria 

 depressa occurs in the southern states, 

 and is very common in the everglades. 

 It forms a large part of the food of the 

 everglade kite, a bird of the hawk 

 family. I have never been able to secure 

 living specimens. It breeds the same as 

 A. gi^as. 



The Planorhes are probably the most 

 popular of the native species. The 

 species of the genus vary greatly in 

 size from one-eighth to more than an 

 inch in diameter. Like the Limnaeas 

 they are found in all parts of the world. 

 They deposit jelly-like masses of eggs 

 which may be readily raised if protected 

 from the fishes. Planorbis trivolvis is 

 one of the most common American 

 species. The red snail is an albino 

 of the common European Planorbis 

 corneus and shows a decided tendency 

 to revert to the normal form. The 

 Planorhes are commonly called orb, 

 posthorn or ramshorn snails. They are 

 hardy and a very desirable addition to 

 the tank. 



The Physas may be readily identified 

 by the left-handed or sinistral shell, as 

 opposed to the more common right- 

 handed or dextral type. The shells are 

 smooth and are from one-half to one 

 inch in length. While this genus is 

 widely distributed, the species are com- 

 paratively few in nvimber. Physa 

 heterostropha is probably more abund- 

 ant than P. gyrina shown on the plate. 



The Potomac snail (Vivipara contec- 

 toides), green apple snail (Campeloma 

 subsolidiim) and Pleurocera etevatum 

 are all worthy of study. The first two 

 named are ovo-viviparious, the Potomac 

 snail being better known to aquarists. 

 The Pleurocera is a trap-door species 

 that contrasts well with the other 

 kinds. All new species should be 

 watched carefully before introduction 

 into the tank, and destructive kinds 

 avoided. 



