ANATINA. 141 
is divided in two parts by a strong deep oblique furrow by 
which it is attached, and may be that in which the artery or 
_vein runs; the lower part of each plate is free, and can be 
raised as far as the furrow; we may say that the branchie, 
instead of being doubled, lay open and present in each the 
same area in one large plate, as if they were in two. The 
furrow gives the appearance of two branchi ; but it must not 
be supposed that the upper portion nearest to the dorsal line 
has been displaced or thrown back by accident; it is securely 
fixed thereto by its membrane, and thus forms a single open 
plate. This branchial arrangement is confined to very few 
families; the Anatine constitute its head-quarters; all the 
species probably have it; in this we have only detected one 
short triangular palpum, but there may be two, or the rudi- 
ment of a second; in A. norvegica, of the same branchial 
form, there are two complete palpi. The foot is bluish- 
white, not lanceolate, in the animal now described; but in 
our notes, written many years ago, it was stated to be lanceo- 
late, and it may be so: this apparent discrepancy perhaps 
originates from the present animal having had a part of the 
valve lacerated, thus preventing the full exsertion of the foot, 
and giving it a blunt and rather clavate extremity. We pro- 
pose this species as the type. 
Live and dead shells are frequently dredged in the coral 
zone at Exmouth, the latter with rarely the ossicle; in the 
live ones great care must be taken not to remove it with the 
animal. 
This species, termed Mya pubescens by the older authors, 
was long considered the young of Pennant’s and our A. de- 
clivis, until, by a suite of specimens dredged by us many 
years since, we demonstrated that it had true specific pre- 
tensions. 
A. INTERMEDIA, nobis. 
A. villosiuscula, Macgillivray. 
Thracia villosiuscula, Brit. Moll. 1. p. 224, pl. 17. f. 4, 7. 
Having examined numerous live specimens of this species, 
it would be a mere repetition of the notes of the type to say 
