54 



AMERICAN FISHERIES SOCIETY. 



Both, or rather all of these are pests, tlie insect forms especially, 

 as they entail a heavy burden upon an important industry. The 

 slugs'are a pest, though the damage done by them is trifling, in- 

 somuch that they are slimy and disagreeable, and therefore a 

 nuisance. There are otlier molluscan forms, which in this con- 

 nection are worthy of notice. 



The common land snail of Europe, Helix hortensis, which 

 annoys the gardeners of portions of the old world by eating the 

 lettuce and other tender vegetables, is found on several of the 

 islands along the Atlantic coast from Newfoundland to Cape 

 Cod, and on the main land, plentifully at Gaspe, Canada East, 

 along the St. Lawrence River, also in Vermont, Connecticut, 

 etc., etc. Another land snail. Helix aspersa, one of the principal 

 European species, and largely used in France and elsewhere on 

 the Connecticut as an article of food, has become naturalized in 

 the gardens of Charleston, S. C, and vicinity, where it has ex- 

 isted forfifty years ; it has also been detected at New Orleans 

 and Baton Rouge, La. ; Portland, Me., Nova Scotia, etc. In 

 addition to those named another well known land snail, Sterwgyra 

 decollata, is numerous in Charleston, S. C, where it has been liv- 

 ino- for many years. It is also found in Cuba and Brazil. I 

 found it abundant in January, 1869, in Charleston, among the 

 ruins caused by the civil war. These three species of mollusks, 

 as before mentioned, are indigenes of Europe, and have been in- 

 cidentally introduced through commerce into the portions of 

 Eastern North America I have indicated. 



By the same medium, one of our American species of pond 

 snails has been transported to England. In November, 1869^ 

 the late Dr. Jeffreys announced the discovery of Planorhis 

 dilataius, in the Bolton and Gorton canals at Manchester. Sus- 

 pecting that this American species had been introduced into the 

 canals through the cotton mills, he v^^rote for information and 

 learned that in one habitat, the waste from the first process or 

 " blowing machine," was discharged close to that part of the 

 canal where the Planorbis occurs. This little mollusk was 

 doubtless conveyed in the raw cotton, either in the &%% state or 

 otherwise, from some point in the Southern States. 



It is not necessary to enlarge by adding to the illustrations 



