223 



The ribs are more delicate than in F. philippiano, the foramen 

 subrotund, much inclined forward. The ribs are sometimes obsolete, 

 sometimes granulose. 



O. ARCUATA G. B. Sowerby Jr. PI. 62, figs. 31, 32. 



Shell small, about the size and shape of G. gibberula of the 

 Mediterranean ; ovate, narrower in front ; very much elevated, the 

 apex decidedly anterior, the front slope short and steep, the posterior 

 slope quite convex ; basal side-margins arched, so that the shell 

 rests upon tbe two ends alone. Surface lusterless, covered with fine 

 subequal or alternating radiating riblets, which are closely but 

 strongly beaded by the otherwise inconspicuous concentric striae. 



Color white, unicolored or rayed with light brown. Inside white ; 

 hole-callus wide, not perceptibly truncated posteriorly, margin finely 

 crenulated. The hole is very small, narrow, about one-twelfth the 

 length of the shell. Length 94, width 6, alt. 4-5 mill. 



St. Thomas, West Indies. 



F. arcuata G. B. SOWERBY 2ix, Thes. iii, p. 199, f. 163, 164. 



This is a very distinct little shell, comparable in its gibbous form 

 and arched side-margins to G. gibberula Lam. The sculpture is 

 finer than in that species, however. From the G. minuta Lam., 

 the most abundant small species of the West Indies, this convex lit- 

 tle form differs notably. 



G. MINUTA Lamarck. PI. 62, fig. 27. 



Shell small, oblong, depressed, the sides subparallel, the summit 

 situated at the front third of the total length ; front slope straight, 

 posterior slope convex ; finely sculptured with radiating riblets 

 (obscurely alternating in size), decussated by numerous fine raised 

 concentric Iira3 which regularly bead the radiating riblets. 



The shell is thin, yellowish or white, having 7 or 8 broad black 

 rays, usually formed of distinct black lines. These rays are visible 

 inside through the thin shell. Hole small, the shape of the shell. 

 Internal hole-callus bordered by a black line ; border finely crenu- 

 lated ; basal side-margins more or less arched, so that the shell rests 

 upon the ends alone. Length 10, breadth 5, alt. 2 mill. 



Turtle Harbor, Florida to Guadelupe. 



F. minuta LAMARCK, An. s. Vert, vi, p. 15. F. gemmulata 

 EVE., Conch. Icon. f. 121, 1850. ARANGO, Faun. Mai. Cub. p. 

 228. BALL, Catal. Mar. Moll. S. E. U. S. p. 170. F. minuta 'Sows., 

 Conch. Illustr. f. 16. Sown., Thes. iii, p. 199, f. 169. (Not, accord- 



