MAZATLAN UNIVALVES 383 
S. W. Mexico, common, P. P. C.—La Paz, Iieut. Green.— 
Mazatlan ; extremely rare; L’pool Col. 
Tablet 1823 contains a fine specimen, mended after repeated 
fractures, with Vermetus and attachment of Crepidula onyx. 
Tablet 1824 contains a minute white transparent shell, (off 
Spondylus ;) smooth below, angulated above, with linear aper- 
ture ; which may possibly prove to be the young of this species. 
449. STROMBUS GRACILIOR, Sow. 
Tank. Cat. no. 1792, p. xx.— Wood, Ind. Test. Suppl. pl. 4, 
f. 1.—Sow. Thes. Conch. p. 32, no. 35, pl. 8, f. 73.—Kien. Icon. 
Conch. p. 31, pl. 21, f.1.—Lam. An. s. Vert. vol. ix. p. 713, 
no. 36.—Ducl. in Chén. Ill. Conch. pl. 17, f. 6, 7.—Kust. 
Conch. Cub. p. 36, pl. 4a, f. 6,7.—Rve. Conch. Icon. pl. 16, 
f. 38.—Mke. in Zeit. f. Mal. 1851, p. 22, no. 95.—C. B. Ad. - 
Pan. Shells, 112, no. 123. 
Known from its Caribbean analogue, S. pugilis, not only 
by its more slender outline, the faint development of the 
tubercles, obsolete on the last whirl, and the preponderance of 
yellow over red in the tint ; but by the epidermis, which is soft 
to the feel, very finely striated, adherent, and generally stained 
green by vegetable incrustations. A wholesale dealer in boxes 
of the W. Indian shell, states that this is a constant character 
of difference. Almost all the specimens had been repaired after 
more or less severe fractures. The shell varies in the amount 
of elevation of the spire. The first whirls have close radiating 
ribs instead of tubercles, crossed by spiral striz. An adolescent 
sp. measures long. 3°24, long. spir. 1°38, lat. 1°74, div. 60°. 
Anvaduldsp.. et caikhe 5 "S84... "2 OS. 0 nee gs 
Hab.—St. Elena and Panama; sandy mud, 6—l10fm.; Cum- 
ing.—Taboga; 1 dead sp. C. B. Adams.—Taheite, Jay. [?]— 
La Paz, Lieut. Green—Mazatlan; very rare; Z’pool Col. 
Tablet 1825 contains an adolescent, and an adult sp.—1826, 
1 sp. mouth darkly stained.—1827, 1 sp. labrum renewed after 
severe fracture. 
