SS eee i 
MT 
MOLLUSCA IN THE NEIGHBOURHOOD OF PONTEFRACT. 471 
S. ovale, Ferrus.— Once abundant in the canal near Nor- 
manton; now much scarcer. 
S. lacustre, Mull.—Brick-ponds near Ackworth. 
Pisidium amnicum, Mull.—Knottingly ; local. 
P. fontinale, Drap.—Stream at Brotherton, and in the Went. 
Var. pulchella, Jenyns.—Ferrybridge and River Went. 
P. pusillum, Gmelin.—Common. ‘In 1864 I collected four- 
teen specimens of this species from a patch of damp moss in a 
ploughed field where there was no ditch or other place where 
water could remain.”—-J. Wilcock in MS. 
P. nitidum, Jenyns. Shining Pisidium.—Said to be frequent. 
I once found a few specimens among damp leaves in Holywell 
Wood, near Pontefract, where there was no water. Mr. Wilcock 
has found a variety of this species with a small plate attached 
— 
to the umbo, similar to the variety Henslowana of P. fontinale, — 
but which could not be referred to the plated variety splendens 
of nitidum. 
Fam. Unrionip=. 
Unio tumidus, Phil. Common Pond Mussel.— Knottingly 
and River Went. Much less common in the Castleford Canal 
than formerly. Many deformed shells occur which have been 
broken by vessels, by dredgers, or by other means in the canals, 
and then repaired. Many are repaired which have had one end 
rubbed or ground off by passing vessels. 
Var. radiata, Colb.—F requent. 
U. pictorum, Linn. Painter’s Mussel.—Knottingly and River 
Went; not so frequent as formerly. The valves of this species, 
smooth and pearly inside, were formerly used by painters for 
holding colours; hence the name. In the York Museum there 
is a shell of Helia aspersa which had been used by the Romans 
as a spoon; it was found, along with various other little utensils, 
among the débris of a Roman household. 
Anodonta cygnea, Linn. Swan Mussel.—In the neighbour- 
hood of Knottingley and in the River Went this species is not 
uncommon. 
Var. radiata.—Near Askern. 
Anodonta anatina, Linn.—River Went. 
Var. radiata.—River Went. 
