18 SOLENID^. 



The locomotion of this species is the same as that of 

 8. pellucidus. Its foot is permeated by a series of aqui- 

 ferous ducts or canals, causing a great expansibility of 

 that organ. Gould says that the animal is " too long 

 for the shell ; " but its power of contraction equals that 

 of its extension. A distorted specimen, found by Mr. 

 Barlee, and now in the University Museum at Oxford, 

 is bent in an extraordinary degree. Whether the curve 

 of such a crooked generation might in course of ages be 

 increased, so as to form a nearly complete circle, would 

 be a curious speculation. 



In the time of Aldrovandus it was called by the 

 Venetians "cappa longa." Linne doubted whether it 

 were not a variety of S. siliqua. The one certainly in- 

 habits deeper water than the other, and they are closely 

 related in form. The present species is Lister's S. curvus 

 (accidentally binominal), the Hypogaa falcata of Poli, 

 Ensis magnus of Schumacher, S. ensiformis of S. Wood, 

 and Ensatella Europcea of Swainson. 



3. S. si'liqua*, Linne. 



S. siliqua, Linn. S. N. p. 1113 ; F. & H. i. p. 246, pl.xiv. f. 3, and (animal) 

 pi. I. f. 1. 



Body similar to that of 8. ensis, except in being rather less 

 compressed, and in the foot being yellowish-white, with its 

 extremity abruptly truncated, and marked with extremely fine 

 close-set and very pale lead-coloured lines. 



Shell so closely resembling that of 8. ensis, except in being 

 of a much larger size, that it is sufficient to mention the few 

 particulars in which they differ. This is almost straight in- 

 stead of curved, much deeper in proportion to its breadth, and 

 more solid ; the margins at both ends are abruptly truncated ; 

 the cardinal teeth in the left valve are blunter, and sometimes 

 cloven ; and the lateral tooth in this valve is often double. 

 L. 1. B. 8. 



* A pod. 



