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Dentition of Pulmonate Mollusks. 83 
Onchidium. 
Onchidium Schrammi, Bl. and Binn. Pointe a Pitre, Guade- 
loupe. Mr. A. Schramm. 
Pl. III, Fig. A. Both the teeth on each transverse row, and the rows 
themselves, are greatly crowded. The general arrangement of the lingual 
membrane is the same as I have described for that of Onchidella in Terr. 
| Moll., V. 
Onchidium is allied to the preceding genera merely by the 
‘) absence of a jaw. 
HOLOGNATHA VITRINEA. 
This section includes genera furnished with a jaw in one single 
piece, and marginal teeth of the lingual membrane acwuleate. 
Sitenopuse. 
Stenopus decoloratus. Demerara. Mr. J. 8. Gibbons. 
Jaw low, wide, slightly arcuate: ends blunt and but little attenuated ; 
cutting-edge without median projection. 
Lingual membrane (pl. XVII, fig. M) long; teeth 23-1-23, arranged en- 
chevron; centrals small; upper margin elongated, tricuspid; no lateral teeth; 
-all the side teeth are aculeate marginals; those nearest the median line some- 
what modified in shape. 
Not having examined a living specimen, I am not able to say 
whether the species has the caudal appendage characteristic of 
Stenopus. 
imax. 
For description of jaw and lingual membrane, see Terr. Moll. 
U. S., V. ; 
Limax semitectus, Morch. Costa Rica. Dr. W. M. Gabb. 
Jaw (pl. XV, fig. I) smooth, arched, ends attenuated; a median projec- 
tion to the cutting-edge; a reinforced space on the centre of the jaw. 
The lingual membrane (pl. II, fig. G) is long and narrow. There are 
441-44 teeth. The centrals have side cusps and cutting-points. The late- 
rals, twelve in number, on each side of the central, are bicuspid; the mar- 
ginals are aculeate,—all of them are bifid by having the side spur often 
_, found on the side marginals in this genus. The 13th, 14th and 15th teeth 
_ form the transition into the marginals. 
The figure gives the central, the first lateral on one side of the 
median line, and two marginals, the sixteenth and forty-fourth 
teeth. 
