42 SOLENIDJ;. 



and force, much to the amazement of him who may lay hold of it, 

 thinking to make an easy capture. 



The animal is cylindrical, too long for the shell, the foot, club- 

 shaped and obliquely truncated, projecting from one end, and the 

 short siphons, united nearly to their fringed tips, issuing from the 

 other. The siphons are quite short, with sixteen internal branchial 

 cirri, and six long and six short ones to the anal opening. It is 

 often used as an article of food under the name of long claniy 

 razor-fish, knife-handle, &c. When properly cooked it is said to be 

 among the most delicious of shell-fish. These names are enough to 

 suggest an idea of the shell to any one who is not already familiar 

 with it. 



Some doubts have been entertained as to whether the European 

 and American specimens belong to the same species. It is certain 

 that our specimens are much the largest and the least slender. 

 Five specimens, each six inches long, measured in height, English, 

 six eighths of an inch ; American, nine eighths of an inch, and this 

 is about the usual proportion. None of the plates referred to well 

 represent our shell. It may at least be properly designated as va- 

 riety Americanus. 



Genus SOLECURTUS, Blainville. 1824. 



Shell transverse, elongated, equivalve, the beaks small, sul^cen- 

 tral, margins nearly j)arallel, ends abrujitly rounded ; hinge with 

 two or three cardinal teeth in each valve ; ligament prominent, 

 seated on thick callosities ; pallial impression with a very deep 

 sinus. 



The above generic definition will include all the shells originally 

 embi-aced in tlie genus by Blainville, except those of his first di- 

 vision, — ''shells compressed, thin, with an interior rib passing 

 from the beaks to the basal margin." An acquaintance with the 

 animal has shown the necessity of sul)dividiug his genus. Mr. Sow- 

 erby proposes to limit it to the species having the interior bar. But 

 Deshayes, in his edition of Lamarck, has already limited the genus 

 to shells of a different type ; and it Avould, therefore, seem most 

 proper that any new name which may be given should be applied to 

 other forms. I have, therefore, separated those with the interior 

 bar and other peculiarities for a new genus. 



If we adopt Deshaycs's modification of the genus, so that it shall 



