THE NAUTILUS. 65 



the evolution of terrestrial life from aquatic, and what physiological, 

 and eventually anatomical and embryonic changes are involved, 

 must be left to the scientists. 



The following observations may be worthy of notice in this con- 

 nexion. In low woods, north of Geneva, Ohio, Segmenting armigera 

 (Say) were found alive in company with Spher. occidental, and in 

 the same woods Physa gyrina were found, then mostly dead shells, 

 where they could not have been transported from any permanent 

 body of water. 



In damp woods at Kenmore, Summit Co., Ohio, among patches 

 of various terrestrial mosses, a few dozen Amnicola limosa Say 

 (.4. parvaf), living and of various ages, were found (late August), 

 and with them a few puerile Physa apparently sayi Tappan. 

 No water was standing in the woods, even after heavy rains, and 

 moreover these snails or their parents must have survived e. g. the 

 exceptionally hot and dry summer of 1911. 



In July of that summer, in a marsh near Hudson, Ohio, which 

 had been dry as a bone for weeks, like hundreds of others, Dr. Rush 

 and I found several dozen specimens of Lymntea apparently lanceata 

 Gld., living and in good condition, clinging to stems and leaves of 

 sedges (Carex and Scirpus), several inches above the ground. There 

 is hardly a doubt that they had been gathering all the moisture they 

 could from dew at night. 



In woods of that vicinity we found Pisidium nbidtum subro- 

 tundum, typical, full-grown to young, under dead leaves in a damp 

 spot. Other Pisidia have been found at similar places, and also in 

 swamps among mosses, out of water, and even on steep banks where 

 water could never be standing. 



Small Lymncea, apparently parva Lea, are often found in green- 

 houses, on mossy flowerpots, sometimes in large numbers, evidently 

 doing well and propagating. 



Similar observations have doubtless been made by other 

 malacologists. 



