454 UMBONIUM. 



U. GIGANTEUM Lesson. PL 58, figs. 17, 18, 19. 



Shell large, depressed, solid ; slate-colored or reddish above, with 

 a series of black spots below the suture, sometimes alternating with 

 white ones, the periphery usually encircled with a row of white 

 blotches ; base largely white, with a dark streak encircling the callus ; 

 spire low, conoidal ; whorls 7, plane, the last often somewhat con- 

 cave above, rounded at the circumference, slightly convex beneath ; 

 surface shining, smooth, with a few (usually 4) narrow spiral im- 

 pressed lines just above the periphery, which are obsolete in the 

 adult. Base convex, callus white, or partly brown or ashen ; in the 

 middle there is a prominent, blunt, heavy tubercle. Aperture 

 oblique, subquadrate. Alt. 16, diam. 27 mill. 



Japan. 



Rotella gigantea LESSON, Illust. de Zool., t. 17, 1831. KIENER, 

 Spec, et Icon. Coq. Viv., p. 6, t. 3, f. 7. SOWERBY, Thes. Conch, v, 

 p. 136, f. 15, 16 ; and in Conch. Icon, xx, f. 3. Globulus giganteus 

 Less., PHILIPPI, Conchyl. Cab., p. 50, t. 8, f. 1. Rotella aucta 

 SOWERBY, Genera of Shells, f. 3. REEVE, Conch. Syst., t. 216, f. 3. 

 Umbonium giganteum A. AD., P. Z. S. 1853, p. 188 ; Ann. & Mag. 

 N. H. xi, p. 265, 1863. DUNKER, Ind. Moll. Mar. Jap., p. 134, 

 1882. 



The largest species of Umbonium. The nearly smooth surface 

 blotched periphery and central tubercle on the callus pad distinguish 

 it. Included in my grouping of species with vestiarium etc., but 

 more allied to costatnm. 



U. COSTATUM Valenciennes. PI. 59, figs. 34, 35. 



Shell heavy, solid, depressed, spire low-conoidal, periphery 

 rounded ; color whitish or light yellow, closely tessellated all over 

 with blackish-olive or reddish-brown squarish spots; surface shin- 

 ing, polished, with strong spiral grooves above, generally 4 to 6 on 

 last whorl ; sutures narrowly ynpressed, with a rather wide margin 

 below them, which often shows a slight tendency to be tuberculate ; 

 base smooth, tessellated around the irregularly convex, flesh-colored 

 central callus ; whorls 6, the last a little concave above, convex 

 beneath ; aperture subquadrate, pearly inside ; callus circular, 

 heaviest in front of the aperture and behind the collumellar lip. 



Alt. 11, diam. 17 mill.; alt, 20, diam. 26 mill. 



Corea ; Japan. 



