ODONTOSTOMUS. 47 



O. BAIIIKNSIS (Moricand). PI. 9, tigs, 10, 17. 18. 



Shell openly ri mate-perforate, fusiform, thin, bluish or brownish- 

 white with interrupted and ragged opaque-white streaks (sometimes 

 wanting), and usually an interrupted brown stripe behind the lip. 

 Surface glossy, covered with excessively fine and close spiral striae. 

 Outlines of spire convex, the apex rather obtuse ; whorls 7 to 7J, 

 hardlv convex, the last tapering downward, somewhat pinched at the 

 base. Aperture oblong, subvertu-al, whitish within, frequently hav- 

 ing a broad brown stripe within the lip, interrupted at the middle of 

 the outer margin, or reduced to two brown spots. Outer lip thin, 

 white, well expanded. Columellar lip reflexed, a groove at its junc- 

 tion with the body of the shell. Columella having a, moderately 

 strong fold above, upon which is superposed a small, acute entering 

 columellar lamella. 



Length 18, diam. 0, length of aperture 8 mill. 



Length 20^, diam. 6, length of aperture 9 mill. 



Brazil : in woods at .Bahia (Blanchet). 



Hflix (Cochlogena) bahiensis, MORICAND, Mem. Soc. Geneve vi, 

 pt. 2, p. 541, pi. 1, f. 6 (1833); vii, p. 438 Bulinnis bahiensis DES- 

 HAYES in Lam., An. s. Vert., viii, p. 252 POTIEZ & MICHAUD, 

 Galerie i, p. 134, pi. 12, f. 11, 12. REEVE, Conch. Icon., pi. 64, f. 

 442 PFR., Monogr. ii, p. 96 ; iii, 376 ; iv, 445 ; vi, 80 HIDALGO, 

 Journ. de Conchyl. 1870, p. 63 Odontostomus bahicola MOERCH, 

 Catalogus Conchyliorum Yoldi, p. 28 (1852). 



The wide basal arch of the aperture is characteristic, as well as the 

 form of the columella, which appears to bear twin folds. Many 

 specimens are without opaque white markings, and frequently the 

 lip stripe of brown is much reduced or wanting; and in fact Mori- 

 caud's description and figure show that the type was a plain and 

 stripeless individual. 



The var. bahicola of Morch (pi. 9, fig. 16) does not seem to me 

 to have any but individual characters. It is defined as "differing 

 from the preceding in the more slender shell with longer aperture, 

 smaller and scarcely divided columellar fold, and gray color." 



0. bahiensis is shown by the intermediate species occultus to have 

 been derived from *a four-toothed stock, like 0. ringens ; the white 

 break in the brown lip-stripe being the vestige of a former upper 

 palatal fold. In this case the pigment glands of the mantle have 

 retained their former interruption after the tooth which induced it 

 has become obsolete and lost. 



