Dentition of Pulmonale Mollusks. S3 



Oaicliidimii. 



Onchidium Schrammi, Bl. and Binn. Pointe a Pitre, Guade- 

 loupe. Mr. A. Schramm. 



PI. Ill, 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., Y. • 



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 aculeate. 



Slenopu*. 



Stenopus decolor atus. Demerara. Mr. J. S. Gibbons. 



Jaw low, wide, slightly arcuate : ends blunt and but little attenuated ; 

 cutting-edge without median projection. 



Lingual membrane (pi. 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. 



Xot having examined a living specimen, I am not able to say 

 whether the species has the caudal appendage characteristic of 

 Stenopus. 



Umax. 



For description of jaw and lingual membrane, see Terr. Moll. 

 U.S., V. 



Limax semitectus, Morch. Costa Rica. Dr. W. M. Gabb. 



Jaw (pi. 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 (pi. II, fig. G) is long and narrow. There are 

 44-1-44 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. 



