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Dentition of Pulmonate Mollusks.. Q 
species in which the dentition of muscarwm and picta may be 
looked for. The others will probably agree with varvans, ete. 
~The jaw of varians, gallopavonis, Troscheli, rwfoapicata, 
graminicola, is high, arched, without ribs, with a blunt median 
projection. Inone species, Milleri, the jaw is like this, except- 
‘ing that it has one decided, stout, central rib, denticulating 
either margin. ‘This shows that the presence or absence of ribs 
on the jaw cannot be considered a reliable generic character. 
(See, also, Dentellaria. ) 
Hemitrochus varians, Mke. (See Terr. Moll., V.) 
Hemitrochus Troscheli, Pfr. New Providence, Bahamas. 
Goy. Rawson. 
Jaw as described ; a strong, transverse line of re-enforcement. 
Lingual membrane (PI. IV, fig. A) long and narrow. Central teeth very 
long ; the upper margin of base of attachment greatly produced above ; the 
reflected portion not extending to the lower margin; median cusp with a 
short, blunt cutting point; side cusps and cutting points obsolete. Laterals 
| like the centrals, but asymmetrical ; the upper margin still more produced ; 
outer laterals with bifid inner cutting point, and side cusp and cutting point. 
_Marginals quadrate, with one large, oblique, rounded, bluntly bifid cutting 
point, and one or two side, small, blunt cutting points. The membrane is 
peculiar in the extension of the upper margin of the base of attachment of 
the teeth. 
Hemitrochus gallopavonis, Val. ‘Turk’s Island. Gov. Rawson. 
Jaw as described. 
Lingual membrane as described in last species. (Pl. IV, fig. B.) 
Hemitrochus rufoapicata, Poey. Cuba. Mr. Arango. 
Jaw and lingual membrane (PI. IV, fig. C) as described above. 
Hemitrochus graminicola, Ad. Jamaica. Messrs. Vendreyes 
and Gloyne. 
Jaw as described. 
Lingual membrane (Pl. IV, fig. E) as described. Teeth 40-1-40. 
Of the above species, the figure gives one central, the adjacent 
lateral or laterals, and one or more marginals. 
Hemitrochus Milleri, Pfr. Fortune Island, Bahamas. Dr. 
J.J. Brown. 
Jaw differing from that of the above species by the presence of a stout, 
