LEPTOTHYRA. 259 



Operculum (pi. 60, fig. 65) inside yellowish, multispiral, nucleus 

 somewhat excentric ; outside calcareous, white, concentrically coarse- 

 ly striate and radiately marked, except on mai'gin of increment, 

 which is smooth and elevated ; center subconcave and coarsely gran- 

 ulose. 



The synonyms are T. costulosits Sowb., T. costulatus ("Gld") Sowb., 

 and Trochus (Gibbula) swpragranosiis E. A. Smith. 



A well marked form, of wide distribution, of which I have before 

 me many examples, all agreeing in the peculiar operculum. I can- 

 not follow Sowerby's synonymy in this group ; beseems to have unit- 

 ed species from a mere superficial likeness. Here, as in the typi- 

 cal Turbo and Astralium, the characters derived from the opercula 

 are of high specific value, and this organ should be examined before 

 uniting the numerous described species. 



L. NANiNA Sowerbie, 1864. PL 58, figs. 5^, 56. 



Shell minute, umbilicate, suborbicular ; apex obtuse; spirally im- 

 pressed-striate ; apex, subsutural tract and base with impressed ra- 

 diating strife ; white, marked around the periphery with rosy equal- 

 ly spaced spots ; whorls 5, convex ; aperture rounded ; columella 

 thickened ; umbilicus narrow, deep, rounded, radiately plicate on 

 the edge. Alt. 8, diam. 3 mill. 



Ins. Art, Archipelago of N. Caledonia. 



Evidently closely allied to L. Iceta. Operculum unknown. 



L. GRANULOSA Pease, 1868. PL 57, fig. 59. 



Shell small, solid, umbilicate, depressed orbicular, spire but slight- 

 ly exserted, very obtuse ; whorls 4, the first planorboid, upper ones 

 granulose, the last spirally lirate, the iirse about 25 in number, un- 

 equal ; aperture subcircular, deflected above; umbilicus plicate 

 within ; color whitish, painted with broad radiating stripes and 

 spots of reddish brown ; white around the umbilicus. 



Alt. 3^, diam. 4 mill. 



Ins. Ponape. 



The spire is usually slightly shorter than in the figure. 



The aperture does not show the nainute lirre w'ithin its outer mar- 

 gin, and teeth within the base which are found in L. Iceta, and is 

 smaller and more oblique than in X.j9i7 ',</«. 



L. PLUCTUATA Hutton, 1884. PL 64, figs. 47, 48. 



Shell small, rather solid, spirally striated, not iridescent ; color 

 yellowish white or pale brownish, with irregular waved longitudinal 



