266 INVERTEBRATA OF MASSACHUSETTS. 



Sowerby, and he did not pronounce it a European species, but sent 

 the last-named shell as the nearest allied to it of all the species with 

 which he is acquainted, and as it certainly is not identical with that, I 

 shall not venture to claim for it any more remote history than that 

 given by Colonel Totten. 



This shell is so plain as to present no striking mark of distinction, 

 and it is consequently not easy to describe it. Tlie only shells liable 

 to be confounded with it, are the Odostnmia fusca and O. exigua ; a 

 slight examination of the aperture readily solves any doubt on this 

 point. 



Ci'ngula aculeus. 



Shell minute, suh-cylimlrical ; ivhorls convex, covered with regu- 

 lar, microscoinc revolving lines ; aperture ovate ; umbilicus partial. 



Figure 172. 



State Coll., No. 32. Soc. Cab., No. 2359. 



Shell minute, ovate-cylindrical, elongated, light yellowish horn- 

 color ; whorls six, convex, and sepaiated by a deep sutural 

 region ; the two upper ones forming a blunt apex, the lowest 

 rather more than half the length of the shell ; the whole covered 

 with regular, crowded, microscopic revolving lines; aperture one 

 third the length of the shell, oval, oblique, angular behind, the mar- 

 gin simple and entire, barely touching the preceding whorl, some- 

 what expanded, and on the left side elevated, and slightly turn- 

 ed over an umbilical depression or chink ; operculum horny. 

 Length 2^- inch, breadth -^^ inch, divergence 23°. 



Found sparingly on the partially decayed timbers of an old 

 wharf, and plentifully on stones, about low-water mark, at East 

 Boston. 



It is a small, but well characterized shell, distinguished by its elon- 

 gated form, its entire aperture, and the minute spiral lines with which 

 it is covered. It is nearly as long as, and much more slender than, 

 C. miniita. Brown figures two or three species, which closely resem- 

 ble this. 



