226 GLYPHIS. 



strength, giving the surface a latticed appearance; between each 

 riblet lies usually a still smaller one, reaching from the margin to 

 about the middle of the slope. The edge is crenulated, the denti- 

 cles in pairs. Orifice situated two-fifths of the length from the 

 front, small, suboval ; hole-callus smooth, blunter behind but with- 

 out a pit. Color whitish with four triangular brown rays, those at 

 the sides broader. The shell rests upon the two extremities only, so 

 that one can see under it when lying on a flat surface. Length 7*8, 

 width 4'9, alt. 2 - 4 lines. (Krauss.) 



Natal. 



F. cruciata Krauss, Die Sudafric. Moll. p. 67, t. 4, f. 9, 1848.— 

 Reeve, Conch. Icon. f. 96. — Sowb., Thes. Conch, p. 201, f. 291. 

 (not F. cruciata Gould, 1846). 



Group of G. viridula. 



Concentric sculpture subobsolete ; color greenish. 

 G. viridula Lamarck. PI. 62, figs. 22, 23, 24, 25. 



Shell oval, elevated, the slopes nearly straight, summit in front 

 of the middle ; sculptured with separated, closely nodose or subno- 

 dose ribs, having usually inconspicuous intermediate riblets ; no 

 concentric lira',. Greenish, unicolored or with the principal radiat- 

 ing ribs whitish ; bluish-black around the orifice both outside and 

 within. 



The margin is finely crenulated ; inside white ; hole-callus black- 

 ish or encircled by a black line. Principal ribs of the outside about 

 20 in number. Length 26, breadth 17, alt. 10 mill. 



St. Tlwmas, Antigua, Jamaica, etc., West Indies. 



F. viridula Lam. An. s. Vert. (ed. Desh.) vii, p. 596. — Sowb. 

 Conch. 111. f. 13.— Reeve, Conch. Icon. f. 25.— Sowb. Thes., p. 198, 

 f. 62.— jF. bicolor C. B. Ad. 



The obsolescence of concentric sculpture in the intervals between 

 the ribs and the blue-black summit are the prominent characters of 

 this species. The beading of the ribs is variable, often nearly ob- 

 solete. 



G. tegula Reeve. PI. 34, fig. 56. 



Shell ovate, conical, front slope straight, back slope straight below, 

 becoming arcuate toward the summit. Sculptured with low alter- 

 nately smaller, slightly beaded radiating riblets; concentric striae 

 sub-obsolete. 



