152 SOLENIDJL 



Agreeably to our method, this family contains only two 

 British genera, Solen and Solenicurtus ; the first has five, the 

 latter, two species. Solen is a singular genus, its transverse 

 measure in some species being 8 to 1 of the vertical. The 

 foot occupies one end of the shell, the buccal orifice the middle, 

 and the posterior portion contains the short siphons, which are 

 nearly united, except in S. legumen, in which they are somewhat 

 longer and more divergent. They have alliances with the 

 Gastrochanida, and by the long linear branchiae with the 

 Pholades ; but the ample notes on the principal species will 

 give the necessary explanations. 



SOLEN, Linnaeus. 



S. SILIQUA, Linnaeus et Auct. 



S. siliqua, Brit. Moll. i. p. 246, pi. 14. f. 3; (animal) pi. I. f. 1. 



Animal subcylindrical, pale drab ; the mantle is yellowish- 

 white, tumid at the extremities, swelling beyond the margins 

 of the shell, closed throughout, except a central narrow rayed 

 slit, which appears to have no other use than to admit 

 water to the branchiae, in aid of the pedal orifice, which in 

 this family is greatly contracted by the shape and position of 

 the foot; it is also produced into a siphon al sheath, truncate 

 at the extremity, bordered by a fine brown line, and which 

 contains two short siphons, just separate at their termi- 

 nations ; they are never extended much beyond the shell ; the 

 upper is rather the shortest, and of less diameter than the 

 branchial tube ; it is encircled by two rows of irregular cirrhi, 

 which do not quite reach the orifice, the margin of which is 

 plain; the lower one has about twelve rather long, tumid, 

 pointed, white filaments; the upper, about twenty cirrhi, of 

 three lengths and sizes, marked with fine brown lines and 

 blotches at their bases, edges and summits; the branchial 

 siphon has also two rows of similar cirrhi ; in the lower one 



