THE NAUTILUS. 113 



and their descendants are so little affected by the foul water that they 

 are now thoroughly acclimated and are producing young in large 

 numbers used to the surrounding conditions. As this is the case, we 

 may now look for Anculosa praerosa Say in nearly all its old haunts, 

 where it will thrive under conditions which would have proved fatal 

 to its ancestors. Many of our forest snails have been forced, by the 

 clearing of the timber and tilling of the soil, to more or less adapt 

 themselves to conditions not slightly, but very materially changed 

 from those to which they were originally used. One of the most 

 ready to take to the new mode of life was perhaps Pyramidula alter- 

 nata Say, which is now one of the most sociable snails that exists in 

 North America ; this snail can be found in all our cities and doing 

 well surrounded by conditions which are, without the slightest doubt, 

 entirely strange to its nature the rubbish heaps in every back yard 

 harboring hundreds of fine and well-developed specimens in every 

 sta"-e of growth. Another forest snail which has taken kindly to 



C O 



open country life is Polygyra appressa Say. By setting a trap (a 

 board greased with lard, placed about one inch above the ground) in 

 a dark and damp alley between two houses in a low part of the town, 

 I captured in ten nights the following number of snails: 9, 12, 10, 

 13, 26, 23, 18, 21, 12, 11 in all 155 adult specimens; young and 

 immature specimens were not counted. This trap cleaned up all the 

 snails in the immediate vicinity, as after that date the captures began 

 to drop off and at the end of three weeks no more were taken. P. 

 monodon Eack. and ivflecta Say have in a smaller degree taken to 

 open country life and are now common on nearly every railroad cut 

 or fill under old cross-ties, but in nearly every instance deprived of 

 the shade of the trees which seemed to be so necessary to their orig- 

 inal abode. With Pol. albolabris Say and exoleta Binn., however, 

 the change from woodland to open country does not agree. I have 

 for years tried the experiment of transporting these eminently forest 

 snails to places which, while being favorable for their maintenance, 

 were still very different from their native haunts, and the result has 

 been with both species a signal failure, and of three thousand that I 

 transported three years ago, a very few only have managed to sur- 

 vive. They laid many eggs but very few of them ever hatched, and 

 at the present time I doubt if there are twenty living snails to be 

 found. Pol. thyroides Say is perhaps of the larger snails the most 

 hardy, and the least affected by changed conditions. Mr Geo. H. 



