NATURAL SCIENCES OF PHILADELPHIA. 105 



Sphserium rosaceum, Prime. 



This shell I proposed as " Cyclas errans," a number of years 

 ago. Mr. Prime puts it in his synonymy of S. rosaceum. It seems 

 to me, however, that the habits of this mollusc are more like those 

 of S. partumeium, Sa} r , which species is usually found in stagnant 

 water, while Mr. Prime's rosaceum is a river shell. My shells are 

 the most fragile of their class that I have seen. From my present 

 knowledge of species and their habits, I am induced now to reclaim 

 my species. I have found these shells usually adhering to the 

 trunks of the "dwarf button-ball" growing in a stagnant pool ; a 

 more solid variety sometimes occurs in ditches. 



Sphserium simile, Say. 

 Lakes. Abundant. 



Sphaeriuni solidulum, Prime. 



Mohawk River. Not plenty. 



Spkaerium striatinum, Lamarck. 



Mr. Say's description of Cyclas edentula, if read with the un- 

 derstanding that his idea of the anterior and posterior of bivalves 

 was the reverse of the present usage, will be found to accord to 

 the shells here referred to. This species occurs in the outlet of 

 Schuyler's Lake, in swift water among gravel, while S. simile 

 occurs in still water in mud in the same stream. A recent writer 

 supposes striatinum to be the young of simile. This is an error. 

 S. striatinum occurs as far east as the Connecticut River at Spring- 

 field, Massachusetts, and is found in many of the larger streams 

 in New York, Ohio, and States westward. Is very abundant in 

 the Erie Canal, less so in the Mohawk River. It has been found 

 in Oneida Lake. (F. E. Spinner.) 



Sphseriuni transversum, Say. 



Sometimes abundant in the canal. A few may be found in late 

 summer months in the Mohawk River. Evidently a western spe- 

 cies, introduced, though known since 1853 to inhabit the canal. 



Succinea aurea? Lea. 



A small, orange-colored species found sometimes in the month 

 of June around the " Little Lakes" may be aurea. The species, 

 has not been authoritatively determined. 



Succinea avara, Say. 



A large variety, sometimes 11-20 inch long, is found on the moist 

 muddy banks of the Mohawk River, sometimes very plenty, some- 



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