MARINE MOLLUSCA OF THE UNITED STATES. 89 



longitudinally furrowed ; spire short, obtuse ; suture strongly 

 impressed, aperture orbicular ; umbilicus large, deep. Dull ash- 

 color. 



Height 5, diam. 5 mill. 



Casco Bay, Maine. 



6. M. UNDULATA, Sowerby. Fig. IT 4. 



Malacol and Conch. Mag. i. , 26. 



Margarita striata, var. Grcenlandica, Moller, Ind. Moll. Green. 1842. 

 Turbo incarnatus, Couthouy, Bost. Journ. Nat. Hist., ii. 98, t. 3, f. 13. 1838. 

 Trochus tumidus, Montagu, Leth. Suev. t. 30, f. 3. 



Shell orbicular, small, smooth and shining; whorls four or 

 five, convex, with numerous striae, alternately finer and undulated 

 near the sutures by short folds or wrinkles ; umbilicus quite large 

 and deep ; aperture nearly circular, very oblique. Uniform red 

 of various shades. 



Height 7.5, diam. 10 mill. 



. New England. (Eur.) 



Trochus Grcenlandicus, Chemnitz, 1781, may be this species. 



7. M. HELICINA, Fabricius. Fig. 175. 



(Turbo.) Fauna Grcenl. 1780. 

 Margarita arctica, Leach, Ross' Voyage. 1819. 

 Turbo inflatus, Totten, Am. Journ. Science, xxvi. 368, f. 5. 1834. 



Shell small, thin, translucent, shining and globular ; whorls 

 five, convex, with revolving minute lines on the base ; spire low, 

 convex ; suture impressed ; aperture large, circular and expanded; 

 umbilicus large and deep. Pale horn-color. 



Height 5, diam. 6.25 mill. 



New England. 



8. M. CAMPANULA! A, Morse. Fig. 176. 



Shell small, depressed, orbicular, smooth, shining, translucent ; 

 spire minute, pointed, aperture large, companulate. Light olive 

 or horn-color. 



Length 3.5, diam. 7 mill. 



New England. 



9. M. ABGENTATA, Gould. Fig. 177. 



Invert. Mass. Edit. i. 256, f. 174. 1841. 

 Trochus glaucus, Moller, Ind. Moll. Groenl. 1842. 



Shell minute, conical, with an obtuse tip ; pearly white ; whorls 

 four, convex, the last slightly angular, covered with fine, crowded, 

 revolving lines ; suture deep ; aperture circular. 



Height 2.5, diam. 3 mill. 



New England. (Europe.) 



