140 ANATINIDA. 
We have named Periploma, but are not aware that any 
British species has been consigned to it: as to Neera and 
Poromya, newly constituted genera, our reasons for intro- 
ducing them to this family will appear hereafter. 
The Anatinide have some connections with Corbula and 
Pandora, but the greater length, separation, and slenderness 
of the siphons still remind us of the vicinity of the Teliinide. 
A malacological character of high importance is attached to 
this group, which we consider decisive of the propriety of 
merging in Anatina the Lyonsia or Osteodesma, and the 
Thracia and Cochleodesma of authors, which is, that all the 
British members of these genera have only a single branchial 
lamina on each side. Two or three of the Telline have a 
similar structure, but they are mere exceptions to a rule, and 
evidence the point of passage between the Anatine and Telline ; 
but in Anatina it is, we believe, the rule; though we cannot 
positively assert that it apphes to Neera and Poromya, yet 
there is little doubt that it does; but as the species are not 
uncommon in Scotland, we hope that the Northmen will 
enlighten us on this point. 
ANATINA, Lamarck. 
Thracia, Recentiorum. 
A. PHASEOLINA, Lamarck et nobis. 
Thracia phaseolina, Brit. Moll. i. p. 221, pl. 17. f. 5, 6; (animal) 
pl. H. f. 4. 
Animal subovally elongated, moderately thick, pale brown ; 
mantle closed, except a fissure quite anteriorly for the passage 
of a compressed, not very long, spatulate foot, with a rounded 
extremity, and posteriorly, for the issue of two moderately 
long siphons, which are separate nearly their length, but the 
animal always carries them in a divergent posture at the 
extremities; both are furnished at the orifice with a few 
minute rays; the tubes are capable of great inflation. There 
is only one large, suboval, pale brown branchial lamina on 
each side, smooth within and pectinated without ; each lamina 
