194 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



marginal), a Charleston specimen. There are 38 1 38 teeth, with 11 per- 

 fect laterals. 



The genitalia are figured by Leidy (Vol. I. PI. XV. Figs. 5, 6). The geni- 

 tal bladder (6) is small, globular, with a short, narrow duct entering the vagina 

 near its upper end : the penis sac (3) is short, stout, cylindrical, with a median 

 constriction ; it receives the vas deferens and retractor muscle at its apex. 



SUBQENUS OPEAS, ALBERS. 



Animal not observed. 



Shell minutely perforated or rimate, thin, striated, slightly or moderately 

 smooth ; whorls 6-8, rather convex, the last usually compressed ; aperture 

 ovate-oblong, equalling one third to one fourth of the shell's length ; peristome 

 simple, acute, its columellar margin reflected. Size moderate or small. 



East Indies, West Indies, Africa, South America. In our country it has only 

 been introduced into the Southern Region. 



Jaw and lingual dentition : see above, p. 191. 



Stenogyra octonoides, D'ORBIGNY. 

 Vol. HI. PI. LIIL Fig. 4. 



Shell small, elongated, turreted, transparent, with delicate, longitudinal 

 striae, sometimes of a spermaceti white, and sometimes wax-yellow ; whorls 

 about 8, convexly rounded, revolving more closely at apex than elsewhere, so 

 as to form a somewhat obtuse summit, the last whorl less than one third the 

 length of the shell; suture deeply impressed ; columella nearly straight; aper- 

 ture elongated, narrow, rhomboid-elliptical ; peristome simple, its right margin 

 straight, its columellar margin slightly reflexed, protecting a minute umbilical 

 perforation. Length of axis, 13 mill.; diameter, about 3 mill. 



Bulimus octonoides, D'OftB., Moll. Cub., I. 177, tab. XI. Figs. 23, 24; PI. XI. 

 bis, Figs. 22 - 24. PFEIFFER. 



Bulimus subula, BINNEY, Terr. Moll., II. 285, PI. LIIL Fig. 4. W. G. BIN- 

 NET, Terr. Moll., IV. 134. Not of ADAMS. 



Found in the Florida Subregion, at Fort Dallas, Florida, and in several of 

 the West India Islands, Cuba, St. Thomas, Jamaica, Porto Rico. It has also 

 been found in Charleston, South Carolina. 



This species belongs to a somewhat numerous group found in the tropics, 

 wherever the banana and other Musacece flourish ; some of which have the 

 columella truncated, and were formerly arranged under the genus Achatina, 

 like S. octona, though by their natural affinities they are clearly associated. 

 The banana and plantain have, by transplantation, become naturalized through- 

 out the tropics ; and it is highly probable that many shells found with them, 

 which have received different names merely because they have been found in 

 localities far remote from each other, are really identical. This shell is consid- 



