262 INVERTEBRATA OF MASSACHUSETTS. 



and Dr. Loven, who are of the opinion that they are distinct. To 

 some of the small European specimens, parallels might be produced 

 from our largest ones ; but in general the spire of our shell is less de- 

 pressed, has no decided angle bounding the flattened spire, and it is 

 less narrowed forwards. Mr. Sowerby sent a shell labelled Litt. ex- 

 pdnsa, Brown, from the Frith of Forth, which much more closely re- 

 sembles our shell. Dr. Loven has given to a dirty olive-colored shell 

 from the coast of Norway the name of L. squalida ; but it is precisely 

 the same as similarly colored shells of this species. As there is still 

 so much cause for doubt, it seems better, for the present at least, to 

 retain Mr. Say's specific name. 



GENUS LACUNA, TDRTON. 



Shell globose or conical, thin ; spire consisting of a few rapidly 

 enlarging whorls ; aperture semi^lunar ; inner lip oblique, flatten- 

 ed; umbilicus forming a lengthened groove along the pillar. 



LACUNA VINCTA. 



Shell small, ovate~conical, with Jive rounded volutions, encircled 

 by four or five purplish-brown bands, and very numerous, minute } 

 undulating lines. 



FIGURE 168. 

 State Coll., No. 41. Soc. Cab., No. 915. 



Turbo vinctus, MONTAGU ; Test. Brit., 307, pi. 20. f. 3. TURTON ; Conch. Diet., 

 195, f. 92, 93. WOOD ; Index, pi. 31, f. 69. DILLWYN j Catal., ii. 844. MA- 

 TON and RACKETT ; Lin. Trans., viii. 167. 

 Turbo quadrifasciatus, FLEMING ; Brit. Jlnim., 299. 

 Lacuna pertusa, CONRAD j Journ. Acad. Nat. Sc., vi. 266, pi. 11, f. 19. 



Shell small, thin, ovate-conic ; spire pointed, composed of five 

 very convex whorls, separated by a fine and deep suture, of a 

 dingy-white or purplish horn-color ; the lower one encircled by 

 four darker chestnut-colored bands, two of which revolve upon 

 the posterior whorls also ; the surface is also marked by faint 

 lines of growth, and numerous, flexuous, revolving marks, which 

 require a magnifier to render them conspicuous ; aperture nearly 

 orbicular ; outer lip sharp thin and simple ; pillar lip white, flat- 

 tened, and excavated by a smooth, crescent-shaped groove, termi- 



