46 .ODONTOSTOMUS. 



Section Bahiensis Jousseaume, 1877. 



Bahiensis Jouss., Bull. Soc. Zool. de France, p. 311 (October, 

 1877). 



Shell rather slender, thin, composed of 7-11 whorls, the apical 

 ones with minute grating of vertical and spiral riblets. Aperture 

 rounded below, the ends of the expanded or reflexed lip not sep- 

 arated from the whorl by grooves. Folds and lamellse when present 

 all simple and entering except the columellar lamella, which may be 

 vertical. Type 0. bahiensis Moric. 



This section is closely allied to the preceding and following. It 

 consists of two groups of species, the second of which may be sub- 

 divided. 



I. Aperture oblong, parallel-sided, the outer lip rather straightened ; 

 surface smooth, delicately striate spirally ; coloration incon- 

 spicuous, corneous-whitish or brown ; teeth 1 (columellar) to 4 

 (parieial, columellar, upper and lower palatal), with rarely a 

 suprapalatal fold developed. Eastern Brazil. 



Group of 0. bahiensis, p. 46. 



II. Aperture oval or oblong, the outer lip arcuate ; surface pitted, 

 malleate, wrinkled or costulate. Chiefly southern Brazil. 

 a. No folds within the outer lip. 



Group of 0. janeirensis, p. 51. 

 a. 1 Lamellae and folds numerous, 59. 



Group of 0. punctatissimuS) p. 54. 



Group of 0. bahiensis. 



In this group there is never more than a single lamella on the 

 columella, and the surface of the shell is not malleated. 



1. Outer lip without folds; no parietal lamella. 



bahiensis, p. 47 ; reevei, p. 48. 



2. Outer lip with upper and lower palatal folds. 



a. No parietal lamella. 



b. No suprapalatal fold ; diam. about one-fourth the 

 length, occultus, p. 48. 



b. 1 A small suprapalatal fold ; diam. nearly one-third 

 the length, ciaranus, p. 4 th 



a. 1 Parietal and columellar lamellae also present. 

 b. Suture thickened with a white thread, 



albofilosus, p. 50. 

 b. } Suture simple, i ingens, p. 40. 



