MOLLUSCA IN THE NEIGHBOURHOOD OF PONTEFRACT. 473 
Var. subcylindrica.—River Went. 
V. cristata, Mull.—Near Fairburn, on caddis-cases. 
PULMONOBRANCHIATA. 
Fam. LIMneIp2&. 
Planorbis nitidus, Mull. Shining Coil Shell.—Hemsworth 
Dam, and roadside leading to Doncaster. 
P, nautileus, Linn. Nautilus Coil Shell.— Hemsworth and 
other places. 
Var. cristax—Said to be more abundant than the type. 
P. albus, Mull. White Coir Shell.—Hemsworth, Castleford, 
and other places. 
Var. Draparnaldi.—Said to have occurred at Streethouse, 
near Pontefract, and other places. 
P. parvus, Say = glaber of Jeffreys. Smooth Coil Shell.— 
Found by Mr. Charles Ashford at Ackworth about 1878, and 
reported later from same place by Mr. Hugh Richardson. Mr. 
Wilcock gives “‘ Pond at Burton Salmon; rare.” I have never 
yet been so fortunate as to fall in with this species. 
P. spirorbis, Mull. Round-edged Coil Shell. —Common. 
Var. ecarinata ?.— ‘At Stanley I have found specimens 
which agreed with the description of var. ecarinata in being light 
grey in colour, and in having one whorl less than the type, but 
the majority were bluntly keeled. Only in very few the keel was 
obsolete.” —J. Wilcock. 
P. vortex, Linn. Flat Coil Shell.—Frequent near Castleford. 
P. carinatus, Mull. Keeled Coil Shell.—River Went, and 
also in ponds at Castleford. 
Var. disciformis.—Ponds at Castleford. 
P. complanatus, Linn. Edged Coil Shell.—Common in ponds 
at Castleford, Ackworth, and elsewhere. Many of the speci- 
mens at Castleford are very concave on both sides. In some 
the thin keel is slightly recurved. 
Var. rhombea = P. rhombeus of Turton.—Near Askern, and a 
few specimens very indistinctly keeled near Castleford. 
Var. albida.—Near Fairburn, 1885. 
P. corneus, Linn. Horny Coil Shell.— Abundant in two 
or three ponds near Castleford. In the summer of this year 
- (1885), during the drought, they occurred in a shallow muddy 
- pond, a dozen together, scarcely covered with water, in the horse 
ZOOLOGIST.—DEC. 1885. 20 
