LEUCOTINA. 167 



Soft parts unknown. With the genus Leucotina, Mr. E. A. Smith 

 unites Adams' Myonia, proposed for shells of somewhat more elon- 

 gated contour. There seems to be no difference between the two 

 groups of more than specific importance. 



Leucotina contains shells more elongated than the true Actions, 

 but with a similar, though weaker, columellarfold,andthesamepunct- 

 ure grooved sculpture. The genus has therefore been generally 

 held to belong to Actxonidce rather than to the Pyramidellida', some 

 members of which have a somewhat similar aspect. Fischer has 

 constituted a group AcUeopyramis for certain species formerly refer- 

 red by Adams to Mojiojytygma, such as A. striata Gray, fulva A. 

 Ad. and eximia Lischke. These seem to be quite distinct from 

 Leucotina; but the other species of Adams' Monopiygma may, with 

 the exception of some longitudinally ribbed forms, be referred with- 

 out violence to Leucotina. Tryon, in the eighth volume of the 

 Manual, has enlarged Fischer's group more than is justifiable, by 

 including these Leucotinas. 



L. DiAN.E A. Adams. Fl. 18, figs. 68, 69, 88, 89. 



Shell ovate-conic, umbilicate, with elevated spire, the whorls con- 

 vex, the last one ventricose ; white ; transversely strongly lirate, the 

 interstices closely latticed. Aperture oval ; columella uniplicate, 

 the inner lip subreflexed below, outer lip crenulated. {Ad.). 



Bay of Jedo, Japan. 



Act(Bon dianoi Ad.. P. Z. S. 1854, p. 59.— Tornatella diance Reeve, 

 Conch. Icon, xv, pi. 4, f. 19.— Lischke, Jap. Meeres-Conchyl. ii, p. 

 171 ; iii, p. 76. 



L. gigantea Dunker. PI. 18, figs. 92, 93. 



Shell ovate-turritted, white, sometimes yellowish, subsolid, trans- 

 versely regularly costate [see detail fig.]. Whorls 8, convex, 

 separated by impressed sutures, the last whorl half the length of the 

 shell. Aperture ovate ; lip somewhat thickened, sulcate within ; 

 columella sinuous, having a strong fold, the margin a little reflexed 

 in the place of the umbilical chink, half covering it ; apex somew'hat 

 obtuse. Alt. 31, diam. 14 mill. 



Japan. 



Odontostomia gigantea Dkr., Malak. Bl. xxvi, p. 71. — Actceon 

 giganteus Dkr., Index Moll. Mar. Jap., p. 160, pi. 2, f. 8, 9. 



