78 LITTORINIDiE. 



R. Zetlandica, Montagu. 



More or less oval-acute ; whorls scalariform, cancellated by 

 longitudinal and spiral costellte, of which latter there are three 

 on the penult, and five or six only on the last whorl : a smooth 

 broad concave area encircles the base : throat not crenated. 



Plate LXXX. fig. 1, 2. 



Turbo Zetlandicus, Mont. Trans. Linn. Soc. vol. xi. (1811) p. 194, pi. 13, f. 3. — 



TuRT. Conch. Diction, p. 211. 

 Ci/dostrcma Zetlandica, Flemixg, Brit. Anim. p. 312. — Brit. Marine Conch. 



p. 158. 

 Rusoa cyclostomata, Recll'Z, Rev. Zoolog. Cuvier. 1843, p. 104. 

 Cingula scalari/ormis, Brit. iNIarine Conch, p. xlii. fig. 89. 

 Bigsoa Zetlandica, Brou'n, Illust. Conch. G. B. p. 11, pi. 9, f. 79. 



The original representation of this shell in the Linnean 

 Transactions, is so unlike its ordinary shape, tliat the 

 identity of scalari/ormis would scarcely be surmised from 

 a comparison of its Hgure in the " British JMarine 

 Conchology." 



The form varies in some degree as to elongation or 

 abbreviation, but is generally oval-acute, and the shell is 

 moderately strong, not translucent, and of an almost uni- 

 form squalid white, or pale fulvous. The four larger volu- 

 tions are roughened by moderately distant longitudinal ribs, 

 that are more or less distinctly clathrated by spiral costelloe, 

 of which last there are generally three rows on the 

 penult and antepenult turns, and five, besides the extreme 

 basal one, on the body-whorl. The longitudinal ribs, 

 attenuated to lamella?, are continued over the horizontally 

 flattened summit of each volution, but often cease below 

 after the fourth spiral ridge, and are always absent from 

 the broad concave area that lies between the peculiarly 

 prominent fifth ridge, (often of an intensely fulvous hue,) 



