MUSEUM OF COMPARATIVE 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, Pl. IL. Fig. A. Ante, p. 331, 
Onchidium, Buon. 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 under the 
right posterior margin of the mantle : anal orifice separate 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, eto. 
For figure of animal, see Genera of Recent Mollusca; of lingual dentition, 
see W.G. Binney, Ann. Lyc. Nat. Hist. of N. Y., X., Pl. XVI. Figs. 3-5. 
This and the three following genera are marine, and are in many ways dis- 
tinct from the rest of the G'eophila. 
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., Pl. V. Fig. B. 
Distribution world-wide ? 
Peronia, Buatnv. (Onchis, Fér., Oncus, Ag.) Animal elongate-ovate ; like 
the last genus, but with arbusculiform tufts and tubereles on mantle. 
For figure of animal, see Genera of Recent Mollusca ; of lingual dentition, 
see Keferstein in Bronn's Thierr., CIT., Fig. 2. 
Buchanania, Lesson. Like the last genus, but mantle smooth, with a 
large central tubercle and radiating striæ ; oral appendages simple, subulate. 
Chili. 
For figure of animal, see Genera of Recent Mollusca. 
Lingual dentition — ? 
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 
