TURBINACEA. MOLLUSCA. LITTORINA. 257 



It is the smallest of the species of this genus that we find. It is most 

 obviously distinguished from small specimens of the last species by its 

 dead surface, which may be well compared to chased silver ; and, on a 

 more intimate examination, it is found to have more uniform and de- 

 cided revolving lines, and its spire is more elevated. 



I was at first disposed to regard it as the M. cdmea, Lowe ; (Zool. 

 Journ., ii. 107, pi. v. f. 12, 13, 132). But, in the following essential 

 characters belonging to that, it differs from our shell, viz. an acutely 

 pointed spire, an angular aperture, and a uniform yellowish flesh- 

 color. The revolving lines, too, are said to be elevated and sub-distant, 

 terms which allow of much latitude of meaning, but which we should 

 not be likely to apply to the crowded, miscroscopic lines on our shell. 

 They appear quite conspicuous on the figure quoted. The young of 

 M. undulata would answer better to that description. If it is not M. 

 cornea, it has not been described ; Mr. Sowerby hesitates to call it so. 



GENUS LITTOKlNA, FE'RUSSAC. 



Shell thick, top-shaped, spire of a few rounded whorls ; aper- 

 ture entire, rounded-ovate, large ; outer lip sharp, inner lip some- 

 what flattened ; lips not continuous posteriorly ; operculum horny, 

 spiral. 



LITTORINA RUDIS. 



Shell strong and coarse, volutions convex and well defined, 

 with revolving ridges ; pillar flattened, prolonged so as to form an 

 angle in front ; color yellowish. 



FIGURE 165. 



State Coll., No. 39. Soc. Cab., No. 881. 



Turbo rudis, DONOVAN ; Brit. Shells, i. t. 33, f. 3. MONTAGU ; Test. Brit., 304. 



TURTON'S LIN. ; iv. 480. Conch. Diet., 11)7. CHF.M.V. ; Conch., v. t. 185, f. 1853. 



MATON and RACKETT ; Lin. Trans., viii. 159, t. 4, f. 12, 13. WOOD ; Index, pi. 



30, f. 7. LAM. ; An. sans Vert., (Isted.,) vii. 49. FLEMING; Brit. Mm., 298. 

 Turbo obligktus, SAY; Journ. Acad. JWrt. Sc., ii. 241. 



Shell broad-ovate, strong and coarse, generally yellowish 6f 



ash-colored, sometimes orange or olive, for the most part of one 



uniform color, but occasionally banded with white, or blotched 



with some lighter color ; surface marked with very perceptible 



33 



