PECTEN. 53 
Some malacologists think that the P. niveus of the Caledonian 
shores is a variety of P. varius ; we believe from the shell it is 
distinct, but the animal must determine; it has not occurred 
on our southern coasts. The P. tigrinus, the P. obsoletus of 
authors, is frequently taken alive in Exmouth Bay; but it is 
a variety, though ribbed at the margin, of a smoother mould 
than the Scotch specimens, which from their variableness 
have been manufactured into three or four species, as before 
observed. The P. danicus is Scotch, and the P. islandicus 
probably spurious. 
** Shell thin and of vitreous texture, varying from a perfectly symmetrical 
to an oblique outline. 
P. rracitis, Montagu et nobis. 
Lima Loscombii, Sowerby. 
————, Brtt. Moll. ui. p. 265, pl. 53. f. 1, 2, 3. 
We have yet to learn why this animal has received the spe- 
cific title of ‘ Loscombii:” surely the far prior and more ap- 
propriate appellation of the excellent Montagu and_ other 
authors ought to be adopted. We do not understand the 
changing old accredited names for complimentary ones. 
This animal presents no essential difference from that of 
Pecten ; it is even difficult to appreciate the specialties, which 
only consist in the greater length of the three rows of the 
tentacular filaments of the mantle, which are long, close-set 
and numerous, of the various hues of pink and white. We 
have seen twenty of these animals alive; they exhibit the 
same character of the liver, branchiz, palpi, minute foot, pink 
ovaria, of most of the Pectines ; the ocelli in the minuter spe- 
cies are obsolete, but the rudiments of them are perceptible ; 
the same kind of locomotion in the so-called Lima, as in 
Pecten, I have frequently observed when placed im sea-water, 
im a shallow dish, and is effected by opening and suddenly 
closing the valves, with the posterior end in front, and thus 
rapid progress is made. When the adductors are unbent, the 
animal protrudes the mantle and mass of filaments, which then 
appear too large for the shell ; this is not so, as on the slightest 
disturbance all vanishes instantly within the valves. 
