GINGLYMACONCHA. SOLENID&. 261 
2. SoLEN SILIQUA. 
Shell smooth, straight, anteriorly rounded and slightly emar- 
ginated ; obliquely truncated behind, with its angles rounded. 
Epidermis olive, more or less tinted with brown. The respi- 
ratory tubes extremely short ; the foot rounded and much-elon- 
gated ; the orbicular muscles of the mantle coalesce behind the 
middle of the mantle, and is only cirrated at the commencement 
of its junction. Length eight inches; height one inch and 
three-quarters. 
Solen Siliqua, Lister, Anim. Ang. t.v. f.57; Linn. Syst. Nat. 
xu. 1113; Gmel. Syst. Nat. 3223; Knorr, Verg. vi. t. vii. 
f. 1; Penn. Brit. Zool. iv. 83. t. xlv. f..20; Poli, Test. 1. 
9: t. x. f. 11 ad 16; Da Costa, Brit. Conch. 253; t. xvii. 
f.5; Brug. Encycl. Méthod. t. ecxxu. f. 2 6. c.; Mont. 
Test. Brit. 46; M. §& R. Trans. Linn. Soc. viii. 43 ; Flem. 
Edinb. Encyel. vu. 89 ; Wood, Gen. Conch. i. 118. t. xxvi. 
f. 1,2; Lam. Hist. Nat. des Anim. sans Vert. v. 451; 
Dill. Dese. Cat. 58; Turt. Conch. Dict. 158. 
Solen Novacula, Mont. Test. Brit. 47. Varietas monstrosa. 
Hypogeea crinita, Poli, Test. 1. 12. t. 1. f. 47. 
This species is very common in most of the bays and estua- 
ries on our coasts, inhabiting sand and mud. 
The Solen Novacula of Montagu is only a monstrous acci- 
dental variety of this species, wanting the cardinal tooth in its 
left valve. 
Genus 10. ListerRa. 
The shell very long, somewhat cylindric, straight ; the hinge 
nearly terminal ; in each valve with one tooth. The tracheal 
tubes are equal and joined, but not cirrated ; distinctly project- 
ing beyond the margin of the shells: the branchiz are very 
much elongated ; the foot clubbed. 
LISTERA VAGINA. 
Shell straight, somewhat truncated behind; the angles 
rounded, anteriorly obliquely truncated ; its margin thickened, 
