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Dentition of Pulmonate Mollusks. WIG 
which the median is pointed, often bifid. There is much variety in the 
shape and denticulation of the cusps. The middle denticle is always the 
smallest. Teeth aculeate when seen in profile. 
By its jaw, Ge@otis calls to our mind the genua Amphibulima, 
and many species of Bulimulus and Cylindrella. ‘here is some 
resemblance in its lingual dentition to the marginal teeth of 
Orthalicus and Liguus, as well as of Polymita muscarum. It 
also forcibly reminds one of some of the features of the denti- 
tion of Triboniophorus. 
Amphibulima, 
Amphibulima patula, Brug. Dominica. St. Kitts. 
Jaw (Pl. XV, fig. E) slightly arcuate, low, ends attenuated; extremely 
thin and transparent, with prominent transverse strie, divided longitudi- 
nally by about forty-five delicate ribs into so many plate-like sections of the 
same character as those of Cylindrella, Macroceramus, and many species of 
_ Bulimulus. No upper triangular median plates as in Cylindrella. Margin 
serrated by extremities of ribs. 
Lingual membrane (PI. XIII, figs. C, D) from a specimen from Dominica, 
long and broad, composed of numerous horizontally-waving rows of teeth, 
of the form usual in the Helicide, Centrals with subquadrate base of attach- 
ment extended at basal angles, narrowing towards the centre, expanding 
towards the upper edge, which is reflected and tricuspid, extending quite to 
the base of the tooth; the cusps are stout, the median one bluntly pointed, 
each bearing a cutting point. The lateral teeth are of the same type as the 
centrals, but asymmetrical. The marginals are long and narrow, rounded 
at base, narrowed at apex, reflected and bicuspid; cusps short, stout, bear- 
ing a cutting point, and generally a simple modification of those of the 
laterals. The extreme marginals have irregular cutting points, like simple 
papille. Fig. D shows a group of laterals. Fig. C shows the changes from 
centrals to extreme marginals. 
Pl. XIII, fig. A, shows the dentition of the St. Kitts form, fig. B giving 
a group of laterals. 
Lately the question of identity of these shells with the Guadeloupe patula 
has been raised (see Journal de Conchyliologie, X XI, 12). I have, there- 
fore, again carefully examined the lingual membranes previously described, 
to learn if they give any difference worthy to be considered of specific 
value. I have figured teeth from each lingual membrane. I regret not 
having had the opportunity of examining Guadeloupe specimens also, but 
have never been able to receive the latter with the animal; indeed it seems 
