rMlJOXlUM-ETHALIA. 457 



nous at the aperture ; base glabrous ; umbilical area covered by a 

 strong calcareous callus, covering nearly two-thirds of the base ; apex 

 frequently eroded, pearly ; aperture oblique, ovate-rotund ; columella 

 thickened ; lip simple, very acute, fragile. Color grayish-blue, with 

 series of brown dots ; columella white ; callus flesh-colored. 



Alt. 10-13, diam. maj. 14, min. 12-1 mill. 



Sea of Japan. 



Rotella japonica SULLIOTTI, Bull. Soc. Mai. Ital. xiv, p. 70, 1889. 



Unfigured and insufficiently characterized. Sulliotti does not 

 compare with the already known Japanese Umbonium with sculpt- 

 ured whorls and beaded suture. 



U. BAIRDII Ball. PI. 60, figs. 5, 6. 



Shell small, depressed, conic, white, polished, externally porce- 

 laneous, internally slightly nacreous ; nucleus globular, dextral ; 

 whorls 5 or more ; radiating sculpture of occasional faint impressed 

 incremental lines; spiral sculpture of occasional microscopic striae, 

 and a single strap-like band appressed to the suture, and bearing 

 numerous flatfish squarish nodules or elevations, which coronate the 

 whorls ; periphery rounded, base rounded, depressed in the center, 

 which is nearly filled with a mass of white callus having a very 

 finely granular surface. Aperture ovate, margin simple, thin, 

 oblique. Alt. of axis 3J, of shell 4, diam. 5 mill. (Dall.) 



Florida reefs, 200 fms. ; Yucatan Strait, 640 fms. 



U. bairdii BALL, ' Blake' Gasterop., p. 359, t. 21, f. 6, 1889. 

 The specimen is not quite adult. 



Genus ETHALIA Adams. 



Ethalia A. ADAMS, Proc. Zool. Soc. Lond. 1853, p. 189. Type, 

 Umbonium guamense Q. & G. (Rotella). H. & A. AD., Genera 

 Rec. Moll, p. 409. FISCHER, Manuel, p. 822. Liotrochus 

 FISCHER, Journ. de Conchyl. 1878, p. 207. 



I have here used Ethalia in its original sense, for the species 

 grouping immediately around E. guamense Quoy. I am convinced 

 that to these it should be restricted. The species are moderate-sized 

 shells, somewhat between Umbonium and Chrysostoma in texture, 

 depressed, the whorls convex, with a mottled or streaked color- 

 pattern. The callus emitted at the coluinellar-parietal angle of the 

 aperture is tongue-shaped, closing the umbilicus except a rather 



