MAZATIiAN UNIVALVES 383 



S. W. Mexico, common, P. P. C— La Paz, Lieut. Green.-— 



Mazatlan ; extremely rare ; Lpool Col. 



Tablet 1823 contains a fine specimen, mended after repeated 

 fractures, with Vermetus and attachment of Crepidula onjrx. 



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. Steombus geacilioe. Sow. 



Tank. Cat. no. 1792, p. xx. — TFboi, Ind. Test. Suppl. pi. 4, 

 f. l.—Soiv. Thes. Conch, p. 32, no. 35, pi. 8, f. 73.—Kien. Icon. 

 Conch, p. 31, pi. 21, f. I.— Lam. An. s. Vert. vol. ix. p. 713, 

 no. ZQ.—Bucl. in Ch^en. III. Conch, pi. 17, f. 6, l.—Kust. 

 Conch. Cab. p. 36. pi. 4 a. f. 6, l.—Rve. Conch. Icon. pi. 16, 

 f. ^%.—Mke. in Zeit. f. Mai. 1851, p. 22, no. 95.— C. B. Ad. 

 Pan. Shells, 112, no. 123. 



Known from its Caribbsean 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 strire. An adolescent 

 sp. measures long. 3 '24, loyig. spir. 1"38, lat. 1'74, div. 60". 

 An adult sp.„ 3-17, „ '84, „ 2-05, „ 70". 



Rah. — St. Elena and Panama; sandy mud, 6— lOfm. ; Cm»»- 

 iwr/.— Taboga ; 1 dead sp. C. B. ^(^am*-.— Taheite, Jay. [?]— 

 La Paz, Lieut. Green. — Mazatlan ; very rare ; L'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. 



