STROPHOCHEILU.S. O 



dear that Spix intended his ^roup to contain Bulirai with reflexed 

 or turned-over lip (whence the name). The group has been adopted 

 by Albers-Martens, Pfeiffer and others with almeida (p.udicusj as its 

 type, and may be considered firmly established. All other generic 

 or subgeneric names founded upon members of the genus (as here 

 constituted) are considerably later, 1850 to 1860. For their history, 

 see references under the several subgeneric captions. 



Subdivisions of Strophocheilus. 



Strophocheilus, in the enlarged generic sense in which it is herein 

 used, consists of four groups of species, moderately distinct in appear- 

 ance, but difficult to define clearly. 



Subgenus I, STROPHOCHEILUS Spix. 



Shell ovate-oblong, brown or white and rose under a yellow 

 cuticle ; surface smoothish with microscopic spirals or closely malle- 

 ated and wrinkled ; outer lip well reflexed and recurved ; coltimella 

 reflexed, the fold inconspicuous. 



Subgenus II, BORUS Albers. 



Shell ovate, capacious, solid, the spire short ; outer lip either 

 thickened or reflexed, whitish or roseate ; columellar fold low or in- 

 conspicuous. 



Subgenus III, DRYPTUS Albers. 



Shell ovate or elongated, solid, dark brown or zebra-striped, the 

 surface rather smooth ; lip varying from slightly expanded to re- 

 flexed, white or brown. Columellar fold conspicuous or weak. 



Subgenus IV, THAUMASTUS Albers. 



Shell long-ovate, with lengthened spire, striate or wrinkled, some- 

 times decussated ; streaked or banded. Aperture small, less than 

 half the shell's length; outer lip blunt, not expanded or reflexed ; 

 columellar fold weak or imperceptible. This group includes Orpli- 

 nus Alb., preoccupied. 



Subgeuus STROPHOCHEILUS Spix, 1827. 



Strophocheilus SPIX, in WAGNER, Testacea fluviatilia quse in 

 Itinere per Brasiliam, etc., collegit et pingenda curavit Dr. J. B. de 



