362 BULLETIN OF THE 
mantle: orifice of combined genital system behind and below right eye- 
peduncle. 
Shell-plate internal, suboval, slightly. convex, small, with posterior nucleus 
and concentric lines of growth. 
Jaw smooth, with median projection. 
Lingual membrane with peculiarly shaped. teeth, centrals tricuspid, laterals 
bicuspid, marginals aculeate, bicuspid. 
Prince’s Island. 
For figure of animal contracted in spirits, jaw, and lingual dentiuon, see 
Heynemann, Malak, Blatt., XV., PG 
The horn-shaped process only seems to distinguish it from Urocyclus, the 
position of the respiratory orifice from Parmarion. Dentition peculiar. 
Vitrinoidea, SEMPER. Animal limaciform, swollen at its middle, slender 
and tapering behind : tentacles simple? mantle large, anterior, covering the 
shell: no longitudinal furrows above the margin of the foot, and no caudal 
mucus pore: no distinct locomotive disk : external respiratory and anal ori- 
fices on right anterior margin of mantle : orifice of combined genital system 
behind and under right eye-peduncle. 
Shell internal, paucispiral, transparent, globose, rudimentary. 
Jaw smooth. 
Lingual membrane with tricuspid central and lateral teeth, and tricuspid 
aculeate marginals, 
Luzon. 
For figure of animal and lingual dentition, see Semper, Phil. Arch. 
HOLOGNATHA HELICEA. 
Tebennophorus, Bins. (Jncilaria, Bens., Megimathium, Van Has.) Ani- 
mal limaciform, cylindrical, blunt before, slightly attenuated behind: tentacles 
simple: mantle covering the whole back: no longitudinal furrows above the 
margin of the foot, and no caudal pore: no distinct locomotive disk : external 
respiratory and anal orifices near the head, somewhat to the rear of the right 
eye-peduncle: orifice of combined genital system behind and below the right 
eye-peduncle. 
Shell or shell-plate none. 
Jaw smooth, with median projection. 
Lingual membrane long and narrow, centrals and first laterals unicuspid, 
outer laterals bicuspid, marginal teeth quadrate, 
Asia, North and Central America. 
For figure of animal, jaw, and lingual dentition, see Terr. Moll. U. S., V. 
Oopelta, Hzywzw. Body limaciform, subcylindrical, tapering behind: 
tentacles simple: mantle small, oval, more pointed behind: no longitudinal 
furrows above the margins of the foot, and no caudal mucus pore: no distinct 
locomotive disk: extérnal respiratory and anal orifices on the right slightly 
anterior margin of the mantle : orifice of combined generative system behind 
and under the right eye-peduncle, 
