MUSEUM OF COMPAKATIVE ZOOLOGY. 359 



Lingual membrane quite like that of Glandina ; central teeth like marginals, 

 but symmetrical ; other teeth aculeate. 



Natal Colony, Africa. 



For figure of animal and dentition, see Bulletin of Museum of Comparative 

 Zoology at Cambridge, PI. II. Fig. A. Ante, p. 331. 



Onchidium, BuCH. Animal limaciform, elongate-oval : tentacles wanting : 

 mouth with lobate appendages : mantle coriaceous, tubercular, covering the 

 whole back : no longitudinal furrows above the margin of the foot, nor caudal 

 mucus pore : no distinct locomotive disk: external respiratory orifice vmder the 

 right posterior margin of the mantle : anal orifice sejxirate from the last, poste- 

 rior : male external generative orifice under the right eye-peduncle; female ori- 

 fice at posterior of under side of body. 



No shell or shelly plate. 



No jaw. 



Lingual membrane broad: teeth different in shape from those of the terres- 

 trial genera, arranged in very oblique rows ; centrals tricuspid, side teeth all 

 alike, bicuspid, inner cusp small, outer cusp larger, with a greatly produced, 

 oblique, squarely truncated cutting point. 



Bengal, West Indies, etc. 



For figure of animal, see Genera of Recent Mollusca ; of lingual dentition, 

 see W.G. Binney, Ann. Lye. Nat. Hist, of N. Y., X., PI. XVI. Figs. 3-5. 



This and the three following genera are marine, and are in many ways dis- 

 tinct from the rest of the Geophiia. 



Onchidella, Gray. Animal ovate : other characters as in Onchidium, but 

 mantle smooth or granular. 



For figure of animal, see Genera of Recent Mollusca : of lingual dentition, 

 see Binney, Terr. Moll. U. S., V., PI. V. Fig. B. 



Distribution world-wide ? 



Peronia, Blainv. {Onchi.% Fer., Oncus, Ag.) Animal elongate-ovate ; like 

 the last genus, but with arbusculiform tufts and tubercles on mantle. 



For figure of animal, see Genera of Recent MoUusca ; of lingual dentition, 

 see Kefersteinin Bronn's Thierr., CII., Fig. 2. 



Buchanania, Lesson. Like the last genus, but mantle smooth, ^^^th a 

 large central tubercle and radiating strise ; oral appendages simple, subulate. 

 Chili. 



For figure of animal, see Genera of Recent Mollusca. 

 Lingual dentition — 1 



HOLOGNATHA VITRINEA. 



Limax, Linn. Animal attached its whole length to the foot, subcylindrical, 

 tapering behind, bluntly truncated anteriorly : tentacles simple : mantle small, 

 anterior, enclosing a shelly plate : no longitudinal furrows above the margin of 

 the foot, nor caudal mucus pore : a distinct locomotive disk : external anal and 



