CYLICHNA. 325 



C. (Mnestia) alboguttata SM., Ann. Mag. N. H. (4), ix, p. 353. 



Var. : Pale roseate, variegated with numerous round white 

 blotches. 



This species is at once known from marmorata A. Ad., by the dif- 

 ference of form. It is without the contraction just below the ver- 

 tex, the apical umbilicus is smaller and not surrounded by so sharp 

 an edge, the stride above and below are not so strongly marked, and 

 the aperture is not so produced upwards as in that species (*Sw.). 



Subgenus CYLICHNELLA Gabb, 1872. 



Cylichnella GABB, Proc. Acad. Nat. Sci. Phila. 1872, p. 273, type 

 C. bidentata. 



The soft parts of the species are unknown ; so that we do not yet 

 know whether this group belongs to Tornatinidce or to Scaphandri- 

 dce. 



C. BIDENTATA Orbigny. PI. 22, fig. 42 ; pi. 27, fig. 9. 



Shell minute, oblong-oval, shining, smooth, except for indistinct 

 growth striae, and sparse, impressed, spiral lines at the basal part. 

 Spire concealed ; body whorl tapering at both ends ; aperture as 

 long as the shell, very narrow, widened below ; columella short, 

 with a spiral callous fold, and an indistinct nodule below. 



Alt. 2-6, diam. 1-4 mill. 



Cape Hatteras to S. Domingo and Barbados, 7-168 fms. ; Florida 

 to Texas, near low water mark ; St. Helena. 



BuUa.bidentata ORB., Moll. Cuba i, p. 125, pi. 4, f. 13-16 (1841). 

 Cijlichnella bidentata GABB, Proc. Acad, Nat. Sci. Phila. 1872, p. 

 273, pi. 10, f. 2. MORCH, Malak. Bl. xxii, p. 171. DALL, Blake 

 Gastr. p. 4Q.Bulla biplicata LEA, Proc. Bost. Soc. N. H. i, p. 204 

 (1844) ; Bost. Journ. Nat. Hist, v, p. 286, pi. 26, f. 2. Utriculus 

 biplicatiis TRYON, Amer. Mar. Conch, p. 104, pi. 13, f. 213. Cy~ 

 lichna bipficata BUSH, Trans. Conn. Acad. vi, p. 467, pi. 45, f. 14. 

 Oylichna bidentata Orb., SMITH, P. Z. S. 1890, p. 297. 



C. ORYZA Totten. PI. 22, fig. 39 (enlarged). 



Shell not very small, not very thin, translucent, white, regularly 

 diminishing from the middle towards each end, the tip being de- 

 pressed into a shallow pit, and the front being rather pointed ; last 

 whorl enclosing all the others ; surface marked with minute lines of 

 growth, a few revolving lines on the anterior portion, and a few 

 22 



