THE NAUTILUS. 53 



ing towards the anterior end so that the marginals disappear. 

 Waves distinct, in the median zone, two to three simultaneously. 

 * Vertigo tridentata Wolf. Waves seen ; other details in doubt. 



SUCCINEID^. 



Succinea avara Say. Sole with three zones; waves in the 

 median, 3-4, rapidly moving forward, each one drawing along parts 

 of the marginals. The surface layer moves forward and backward, 

 undulating, with every wave passing. When part of the foot is 

 detached from its support, the waves can be seen there proceeding 

 on the more or less contracted and folded sole. 



S. retusa Lea. Three zones, median one with 4-5 waves. 



PALUDESTRINA SALSA, PILSBRY, 



BY KEY. HENRY ^\. WINKLEY. 



It seems odd that a species so widely distributed, and fairly 

 abundant, should have escaped the eyes of New England collectors 

 so long. Yet its dwelling-place is peculiar. A word as to where it 

 occurs may be of interest. It was first noticed by the writer at a 

 spot where a brook enters the marsh at Branford, Conn. The site 

 is probably three miles inland from Long Island Sound, and the 

 water at this spot must be fresh. Later I found it more abundant 

 on vegetable matter in a ditch in the marsh near the railroad in 

 Branford and a mile nearer the sound. The waters here would be 

 brackish. I have not seen the locality where Mr. Owen Bryant 

 found it at Cohasset. Last summer I located it in a pot hole in the 

 marsh at Wareham, Mass. This locality showed it in a pot hole 

 without an outlet. I have not seen it in such a place elsewhere. 

 The locality mentioned in my last article in the Nautilus (vol. 

 XXI, p. 75) where my daughter found it at East Wareham, was 

 among flags near the border of the Agawam river. The character 

 of the water may be understood from the fact that I was in mid- 

 stream examining Unio complanatus when she found P. salsa in the 

 same river. Last winter I took up a residence in Danvers, Mass., 

 and have found P. salsa here. Two localities reveal it ; both are 

 spots where the water ebbs and flows, and not closed pot holes- 



