154 SOLENID^E. 



Pholades. I believe there is no communication between the 

 siphons, but I have not proved this fact by injections, as in 

 Pholas. The branchial transverse vessels, artery, and vein 

 are very distinctly marked ; there are, in connection with the 

 laminae, a pair, on each side, of pale brown, thin, small, 

 delicate triangular palpi, smooth without, striated within. 

 The liver is composed of distinct aggregations of light 

 greenish or yellowish masses, with the ovary united to it 

 more anteally. The crystalline stylet is very long, but the 

 tricuspid membrane or attritor is without much consistence ; 

 it works, however, in the stomach. The general anatomy 

 is in most respects as in Pholas, but it has two adductors, 

 instead of the single post-medial one of that genus, and, as 

 in it, the intestine plunges into the body, then ascends, and 

 runs posteriorly on the dorsal range embraced by the heart 

 and auricles, and discharges into the anal conduit by a white 

 pendulous rectum. The branchial and anal siphons being 

 short, may possibly be confluent as in the short-tubed animals, 

 in which case the entire ventral cavity must be considered 

 as one large branchial siphon, divided by a septum at their 

 termination. 



This animal represents the typical Solens. We may observe, 

 that the long branchial cavity in some measure supplies the 

 place of the elongated siphons of the Pholades. 



S. PELLUCIDUS, Pennant et Auct. 

 S. pellucidus, Brit. Moll. i. p. 252, pi. 13. f. 3 ; (animal) pi. I. f. 2. 



Animal elongated, compressed ; mantle of the palest drab, 

 closed ventrally, without the central assistant branchial slit 

 as in S. siliqua, open at both ends for the passage of the foot 

 and siphons; these latter are very short, scarcely protruded 

 beyond the shell ; the branchial has about ten cirrhi, edged 

 with fine brown lines, with one or two smaller ones between 

 each; the anal tube is plain, or scarcely broken into points of 

 a pale brown, and on both are a few large, rather long, white 

 filaments, springing from the body of the common sheath, 

 just below the siphonal orifices. The foot is much less 



