132 
lateral, tinged with light purple; margin entire; inside 
white with a dark brown muscular impression. 4. 
Bangor, rare, Isle of Man. 
P. PutcHeua. Forbes in Mag: Nat. H.7. p. 591. 
f. 61.—Ovate, smooth, subpellucid, bluish white with 
ten or twelve moinliform red rays (becoming by age 
reddish white and opaque) ; apex acute, submarginal. 
0,16...0,20. Isle of Man. 
P. AncyLoipEs. Forbes, Annals Nat. Hist. 5. p. 
108. ¢.2. f. 16.—An. P. Gusson1. Phillippi. t. 7. f. 7.7? 
—Extremely thin, pellucid, rounded, gibbous, white, 
seeming reticulated when under a lens; vertex inclining 
to the margin; inside bluish white. 9,16. Arran. 
Wonderfully like a marine Ancylus. 
Trise.—SEMIPHILLIDIANA. 
Grnus.—PLEUROBRANCHUS. 
Dorsal and internal, thin, flat and obliquely oval. 
P. Promos. £. p. 291.—Buiita. P. Mont. p. 
214. wig. 2. f. 5. (animal) and t. 15. f. 9.—D. p. 478. 
-—Lin. T. 8. p. 123.—Ovate-oblong, depressed, pel- 
lucid, thin, glossy yellowish white tinged with brown at 
one end, the other minutely convoluted on the back or 
upper part (the convolution making but one tum) 
strongly wrinkled concentrically, and marked with two 
