1893.] NATURAL SCIENCES OF PHILADELPHIA. 245 



it may be possible that the small body absorbs air or oxygen from 

 that contained in the water. In one example which had been sub- 

 merged for more than half an hour, the pulmonary cavity was com- 

 pletely filled with water, and the heart contracted at a rate of 74 

 per minute, in a temperature of about 65° F. The foot was 

 stretched out and moving about, trying to get a hold, but the tenta- 

 cles kept deeply retreated, the dark eyes being visible above the 

 buccal body. 



Vallonia has a very wide geographical range, being distributed all 

 over the temperate region of the Northern Hemisphere. It is evi- 

 dently an old genus, geologically, as it has been found fossil in many 

 places, and its wide distribution in itself is an evidence of antiquity. 

 Three or four species are found on both continents. Of several 

 forms or species, we have yet little information, since they are 

 known only from single or a few localities. A few species have also 

 been found on the southern half of the globe — V. costata in Aus- 

 tralia, jndehella in Australia and Mauritius ; whether they are 

 endemic there, or introduced by trade or plants, etc., it is impossible 

 for us to decide at .present, but the latter seems to be the more prob- 

 able. 



Of their station, we do not know enough to speak in a general 

 way. They are mostly found under wood, stones, at the roots of 

 plants, etc., and seem to be gregarious. They are frequent on 

 mossy cliffs, and often in wet meadows, alwavs, as it seems, more in 

 open places than in deep forests. They are therefore likely to be 

 washed off by heavy rains, and immense numbers of them, especially 

 dead shells, are carried to the water courses and then found in the 

 fine drift — always a matter of importance in collecting shells. 



The materials upon which the present paper was written, are : 

 the Drawer series of Vallonia in the collection of the Academy of 

 Natural Sciences of Philadelphia ("Acad. Coll."), about 35 lots, 

 kindly communicated by Mr. Henry A. Pilsbry ; the reserve ser- 

 ies of the collection of the National Museum, of Washington, D. C, 

 forwarded by the kindness of Mr. Wra. H. Dall, about fifty parcels, 

 and my own collection, now about 100 vials, comprising valuable 

 contributions from MM. O. Staudinger and A. Bang-Haas, of 

 Blasewitz, near Dresden, Germany. Several conchologists of this 

 country, as already stated, were so kind as to collect and send, at my 

 request, living examples of some of our American species. 



