180 LAND AND FRESH-WATEK MOLLUSKS. 



and sixty specimens of pusilla, (not many alive but the shells in good con- 

 dition,) some thirty or so of pygmcea, and about fifty of edentula, besides two 

 or three suhstriata and cylindrical and many commoner shells. 



Vertigo palustris. — A few dozen specimens from the wet grass on the banks 

 of Hemsworth Dam. 



Clausilia nigricans. — Common in the woods among moss on trees, etc. 



Carychium minimum. — Common in the woods at roots of mossy grass. 



Limnseus auricularis. — Not uncommon at Hemsworth and Winterset. 



Limnaeus pereger and its variety lineatus. — Common — varieties acutus and 

 lacustris. — Not common. 



Limnaous palustris. — A few specimens from small field pools. 



Limnseus truncatulus. — Abundant in grassy ditches. 



Limnajus glaber. — Abundant in one meadow pool, confined to a few square 

 yards. The peculiarity giving rise to variety lineatus in the pereger I have 

 observed in all the species of this genus. 



Ancylus fluviatilis. — Not uncommon. 



Velletia lacustris. — 'Pretty common in one small pond, adhering to grass, etc. 



Physa fontinalis. — Abundant in mill pond. 



Aplexus hypnorum. — Not common. 



Planorbis albus. — Good specimens from Hemsworth Dam. 



Planorbis Igevis. — Abundant in one small depopulated fish pond; adhering to 

 Potomoijoeton crispus. Some strange monstrosities. 



Planorbis imbricatus. — Not common: found with v. lacustris. 



Planorbis carinatus. — A few specimens. 



Planorbis marginatus. — Common. 



Planorbis vortex. — Common in stagnant pools. 



Planorbis spirorbis. — Common in stagnant pools. 



Planorbis nitidus. — This well-named species was common in an old fish pond 

 among duckweed a year or two ago, then nearly disappeared, but has again 

 increased. 



Cyclas cornea. — Abundant but small. 



Cyclas lacustris. — Three specimens obtained last year from a stagnant pond. 



Pisidium nitidum. — Common in one small pool. 



Pisidium Henslowianum. — Three specimens hitherto. 



Pisidium amnicum. — Pretty common in running streams. 



Pisidium cinerium? — This and pulchellum, I am not satisfied about; we find 

 here abundantly in one locality a species we can refer only to cinerium. 



Anodon cygneus. — Carted for manure from Nostall: I cannot speak to the 

 varieties; there appear to be puzzling connected links among them. 



Unio plctorum. — Considerable numbers in the Went, near and in Went Vale. 



Unio tumidus. — In same locality, but not so common as the last. 



Dreissena polymorpha. — In the feeding canal from Winterset reservoir: attach- 

 ed in masses to stones as usual, but almost every specimen corroded by the water. 



Flounders Institute, Ackioorth, PoMefract, January 21th., 1854. 



