350 On fa genus Pompholyx and its Allies, 



Sub-genus Limmvrt. I, am. 1K01. ( 



Spire produced, slender. Last whorl expanded, with a fold 

 on the columella. 



Type LiiiiiKta gtagnaUa. Linn. 



Genua AmphipepUa. Nils. 1822. 



Mantle produced over the outside of the shell. Shell few 

 whorled, dextral. 



Type Amph'qx plea <jlut'n\osii. Miill. 



Genus Krinna. II. & A. Adams. 1858. 



Animal yet nndescribed. Shell ovate-globose, spire short, 

 Last whorl much the largest, spire obtuse. Columella straight, 

 excavated, and with a curved elevated external ridge continued 

 in t'n»nt into the outer lip, which is simple and acute. Shell 

 horny, striate longitudinally, dextral. 



Type Ermna Newcomhi. II. & A. Ad. 



Genus Strebelia. Crosse and Fischer. 1808. 



Shell involute; spire short, hardly perceptible; dextral. 

 Animal unknown. (" Much larger than the shell,'' Berendt.) 

 Type Strebelia berendtii - l*h>/sellii herendti. Pfr. 



The fact that some species of TJimruBa l proper, are dextral 

 and some sinistral, is insufficient cause tor placing the latter 

 10 B group by themselves, unless other characters are present, 

 of which at present we have no information, 



Sub family I'i.a.M'KIii.n.k. II. & A. Ad. 



Lateral jaws present. 



Tentacles filiform. Foot short. Genitalia on the left side.* 



• on us Planorbis. Guett. L756. 

 Shell dextral, depressed. 



* If we mnsiiliT tin- shillsnf this group oh dextral, thoy offer the pecu- 

 liarity <if having th<- genitalia m i" most HiniNtral sheila, Pomphotyx pre- 

 .ii,. condition!, ami is c.Tt ainiy dextral. 



