MARGARITA. 



297 



the base still smaller, or (3d) the spiral sculpture obsolete, surface 

 smooth or nearly so above and beneath. The spire is more or less 

 elevated ; apex obtuse ; suture impressed, sometimes subcanaliculate ; 

 body-whorl convex beneath ; aperture oblique, oval-rhomboidal, very 

 brilliantly iridescent within, but the acute peristome has a rather 

 broad marginal band of opaque white; columella simple; umbilicus 

 tubular, with incremental stria? within. Alt. 4-5, diam. 4-5 mill. 



Sitka to San Diego, Cal. 



M. lirulata Carp, (and vars. subelevata, obsoleta and coiiica) Proc. 

 A. N. S. Phil. 1865, p. 61 ; Suppl. Rep. Brit. Asso. 1864, p. 653.— 

 31. var. tenuisculpta Carp. Proc. A. N. S. Phil. 1865, p. 61. — M. 

 acuticostata Carp. Proc. Cal. Acad. 1864, iii, p. 157. — Gibbula 

 optabilis Cpr. Proc. Cal. Acad, iii, p. 214.— Gibbula parcipida Cpr., 

 Ann, and Mag. N. H. 1864, p. 426. — G. sucdnda, G. funieulata 

 and G. lacunata Carp., I. c, p. 426, 427. — M. lirulata (Carp.) Dall, 

 Amer. Journ. Conch, vii, p. 128. 



" After a careful study of the types of the above species, and a 

 comparison of hundreds of specimens collected by Mr. Stearns and 

 myself at Monterey and elsewhere, I am compelled to the belief that 

 they are simply forms of one protean species. They are not even 

 varieties capable of diagnosis ; for not only are the intermediate 

 specimens as abundant as the nominal species, but the characters, 

 singly, are interchanged without limitation." {Dall.) 



The above synonymy is adopted from Dr. Dall. The species, 

 while in the highest degree variable, is easily known fi-om other West 

 American Trochidoe. 



M. FULGiDA Jeffreys. PL 47, fig. 99. 



Shell globose-conical, rather thin, transparent, and of a bright 

 luster ; sculpture, only some very fine and scratch-like spiral strise 

 round the base; color clear white; spire raised; whorls 4, convex, 

 somewhat flattened below the suture ; the last occupies four-fifths of 

 the shell ; apex depressed and regularly spiral ; suture rather deep ; 

 mouth circular, incurved above ; the peristome is not continuous or 

 complete, but similar to that of other species in the present genus ; 

 umbilicus narrow and deep ; operculum filmy, multispiral, with ob- 

 scure lines to distinguish the whorls. 



Alt. -1, diam. .085 in. (Jeffreys.) 



X. Atlantic, lat. 48° 6', long. W. 9° 8'. 539 fms. 



T.fulgidus Jeffr. P. Z. S. 1883, p. 95, t. 20, f 1. 



