ISO HELIX-OXYCHONA. 



whorls slightly convex above, subconcave at the lower part above 

 the periphery ; last whorl very acutely carinated at the periphery, sub- 

 concave above and below the carina, not deflexed anteriorly, gently 

 convex beneath. Aperture very oblique, triangular, showing the 

 bands of outer surface within; peristome above the median angle 

 not at all expanded, sinuous ; basal lip expanded and subreflexed, 

 pink or w r hite, appressed over the umbilicus; terminations of 

 peristome remote ; parietal callous scarcely visible. 



Alt, 17, diam. 20 mill. ; alt. 16, diam. 16 mill. 



Brazil 



Trochus bifasciatus BURROW, Elements of Conchol., p. 188, t. 27, f. 

 2 (1815); 2d. ed. p. 177 (1825). H. (Helicigona) bifasciata FER. 

 Prodrome, p. 37. PFEIFFER in Conchyl. Cab., p. 94, t. 13, f. 1,2.- 

 H. pyramidella WAGNER, in Test. Fluv. Braziliense, p. 22, t. 16, f. 

 1, 2 (1827). Helicina pyramidella SPIX, MSS. of Test. Brazil. 

 Geotrochus pyramidella BECK, Index, p. 47. Helix Bosciana FER., 

 Prodrome, p. 37; Histoire, t. 64, f. 1. LAMARCK,, An. s. Vert., 

 ed. DESK., p. 118. H. blanchetiana MORIC. Mem. Gen. vi, p. 2,t. 1, 

 f. 3; vii, p. 418. Caracolla bifasciata GRAY, Ann. of Phil. n. ser. 

 ix, p. 412. Helix bifasciata REEVE, Conch. Icon., f. 574. PFEIFFER, 

 Monographia i, p. 232. HIDALGO, Mol. Viage al Pacifico, p. 29, t. 

 1, f. 10, 11. 



This species is broader than H. pileiformis, with less convex base, 

 and the umbilicus is completely closed. It differs from H. 

 zhorquinensis in being smaller, less strictly conical, more concave in 

 the spire, and the peristome above the median angle is not expanded, 

 as it is in that species. H. bifasciata is often pure white without 

 bands. 



H. LONCHOSTOMA Meuke. PI. 60, figs. 10, 11. 



Imperforate, orbiculate-conic, beneath a little convex; acutely 

 carinated ; whorls 6, plane, the last trifasciate, and pitted-crenate at 

 the carina, the others so at the sutures ; aperture oblique, lanceolate ; 

 lip-margins reflexed. (Menke.) (Peristome simple, acute, upper mar- 

 gin subexpanded, basal margin narrowly reflexed. Pfr.} 



Alt. 15, diam. 22 mill. 



Brazil, between Rio and Campos. 



Caracolla lonchostoma MKE. Synops. meth. Moll., p. 76 (1828). 

 H. lonchostoma PFEIFFER, in Conchyl. Cab., p. 95, t. 13, f. 5, 6. ; 

 Symbolse, iii, no. 567 ; Monographia i, p. 232. 



