OF THE FIRTH OF FORTH. 87 
Helcion pellucidum 
HT. pellucidum, var. 
shell. Ihave not found it beyond Gul- 
lane shore, where I took a solitary living 
specimen. It is abundant at the Isle of 
May (JZ). 
Note—Where a spring of fresh water 
rises on the shore above low water mark, 
a little to the east of Granton East Har- 
bour, a thin form of P. vulgata, pale, and 
with a silky surface, takes the place of all 
other forms, and is plentiful. It may be 
due merely to the influence of fresh water ; 
but I suspect a corroding quality in the 
spring. Tectura testudinalis in the same 
place is worn very thin. If this form of 
P. vulgata had permanence, its appropriate 
name would be var. sericea (J.). 
(Linn.). 
Firth of Forth (/B.). 
Good specimens common on Laminaria 
all along the North Berwick coast, and 
at Dunbar and Cramond Island (JZ). 
We have found this species at extreme 
low water, at Elie, Aberdour, and North 
Berwick. It frequents the stems and roots 
of Laminaria. 
levis. 
Common in the hollow part (or under 
side) of roots of Laminaria at North 
Berwick; also at Dunbar and Longniddry 
(M1). 
We obtained the variety also at Elie and 
Aberdour, and on the beach in Largo Bay. 
Tectura testudinalis (Miiller). 
Firth of Forth (ZB); beach between 
Portobelfo and Fisherrow (Metz. and Mey.) ; 
Granton (JZ). 
The shell is sometimes an inch long on the 
Edinburgh shores. The markings vary 
greatly, and there is a blue form bearing 
