BIVALVES. SOLEN. 



SOLEN. — Razor-sheatii or Kmfe-iiandle. 



Animal — an Ascidia: Shell hivahcy oblong, open at both 

 ends: hinge v;ith a subulate refwcted tooth, often double, 

 and not inserted in the opposite valve. 



Although the number of species in this genus are but 

 few, viz. twenty-three, yet their shapes, and general ap- 

 pearance, are exceedingly varied. 



In some of the species, as in the Solcn siliqua, vagina, 

 &c. &c. the breadth of the shell is in the proportion of 

 about seven to one of its length, thereby giving it a re- 

 semblance to the handle of a knife, or sheath of a razor- 

 strop; some, on the contrary, though possessing nearly 

 the same proportions, are curved or bent, like the scab- 

 bard of a scimitar, as the Solen ensis, &c. &c. 



In others, the form approaches nearer to some of the 

 truncated species of the preceding genus, being swollen 

 or putfed-up like a bladder; and other specimens afford 

 a likeness to a cockle or cardium. However, the surest 

 criterion how to class the Solen, is by observing both 

 ends of the shell, which invariably will be found open or 

 gaping. 



Tlie next characteristic is derived from the hinge, 

 which usually is supplied with one subulate tootli ; yet it 

 often occurs that this tooth is found double, though not 

 always inserted in the opposite valve. 



The genus Solen, for the most part, contains but little 

 beauty; there are, indeed, some few exceptions— such as 

 the Solen radiatus, roseus, &c. &c. tjiese, from being 

 rayed with purple and white, or h;i\ ing a tmr pink i^o- 



