THE MOLLUSCA OF PONTEFRACT AND NEIGHBOURHOOD. 449 
species and varieties have been discovered. A few new localities 
for species and varieties mentioned in the former list have also 
been added :— 
AQUATIC MOLLUSCA. 
LAMELLIBRANCHIATA. 
Fam. SpHH{RIDz. 
Spherium ovale, Fer.—The station mentioned for this scarce 
species in my previous list (Zool. p. 471) has been searched this 
year, but none could be found. It has, however, turned up in 
the Barnsley Canal at Heath, a few miles nearer Wakefield. 
Three specimens were obtained on Sept. 2nd of the present year. 
Pisidium fontinale, Drap., var. Henslowana.— River Went (J. 
Hebden). Omitted from my former list. 
PULMONOBRANCHIATA. 
Fam. Limneipz&. 
Planorbis complanatus, Linn., var. — On September 16th of 
this year I found several specimens of P. complanatus with the 
keel very obtuse, along with specimens of the type with a sharp 
keel. The variety is horn-colour, large, and covered with Con- 
ferve ; the type is of a clear reddish brown, and not covered with 
Conferve. They all occurred near Milford, and were intermixed 
in one dyke. Our complanatus here, both type and variety, are, 
as before mentioned, very concave on both sides, though the 
species is described in books as being flat or flattish on the 
under side; Tate says, ‘‘ convex.” 
P. fontinale var. pulchella.—Milford, on caddis-cases. 
Bythinia tentaculata, L., monst. scalariforme. — Near Milford 
Junction Railway-station. New to Britain. 
Physa fontinalis, Linn., var. curta, Jeff. — Milford Junction, 
on caddis-cases. 
LTimnea peregra, Mull., var. ovata, subvar. nitida of Zieg.— 
Spine short; mouth expanded, shining. Ditches at Methley. 
L. peregra var. candida.—Milford, one specimen. 
L. stagnalis, Linn. — In May of this year I found a single 
dead shell near Milford (amongst mud which had been thrown 
from a ditch), which, from the appearance of the reflected outer 
lip, was full grown, though only measuring in length 20 mill., 
and in breadth 9 mill. Mr. Cockerell, of Chiswick, who has the 
Shell, states that it is much smaller than the varieties minor 
