176 CHLOROSTOMA. 



beaded upon the upper surface, the interstices between them mi- 

 nutely spirally striated ; on the penultimate whorl they number 

 about 6 ; below the periphery the lirse are finer, closer, and nearly 

 smooth ; last whorl obtusely angulate or rounded at the periphery ; 

 base rather flattened, somewhat concave around the umbilicus, and 

 generally eroded in front of the aperture ; aperture oblique ; outer 

 lip beveled to an acute edge, which is usually margined with green 

 and is sulcated or crenulated, the furrows corresponding to the lirre 

 of the outer surface ; the j^early throat is also more or less sulcate ; 

 columella arcuate, expanded above in a bright green callus which 

 partly surrounds the umbilicus, at its base green, bearing a tuber- 

 cular tooth, followed by several sznaller ones ; basal margin smooth 

 or denticulate within ; umbilicus wide and deep, white or greenish 

 within. Alt. 22, diam. 25 mill. 



Rio Janeiro, Kortlnvard to West Indies. 



Trochus viridulus Gmel., Syst. Kat., xiii, p. .S574. — Philippi, 

 Conchyl. Cab., p. 75, t. 14, f. 5. — Fischer, Coq. Viv., p. 210, t. 70, f. 



1 (not T. viridulus Mke.) — T. Cruciatus "Chemnitz," Philippi, 

 Conchy!. Cab., p. 76, t. 14, f 8 (not of Linn.) — T. artievlatus d'Orb., 

 Voy. dans. rAmcr. Mcrid., p. 409. 

 Under the above specific name I am comjielled to unite a numl)er 



of species hertofore considered distinct. The descriptiim and figures 



given above apply to the typical form found on the E. Coast of S. 



America. This form is nearly always green beneath the superficial 



coat. 



Var. RETicuLATUM Wood. PI. 29, figs. 63, 64, 68, 69. 



This form is more depressed than C. viridulum and smaller; the 

 base is flatter ; the periphery carinate ; the lirce of the upper surface 

 more regular, more distinctly beaded, the interliral interstices with 

 fewer spiral stride, often with minute beaded lirula^. Coloration as 

 in C. viridulum, consisting of radiating stripes. Aperture and 

 columella tinged with green or white. Alt. 15, diam. 18-19 mill. 



Panama to Mazatlan. 



T. retieulatns Wood., Ind. Test. Suppl, t. 6, f 38. — Fischer, Coq. 

 Viv., p. 212, t. 70. f; 2.— T. brazilianns Menke, Syn. meth. Moll., p. 

 142 (1830).— Philippi, Conchyl. Cab., p. 76, t. 14, f 10. 



A form precisely like this in every character except that it has a 

 somewhat more rounded perijjhery is before me from the Gulf 

 coast of Costa Rica. 



