[From rae Annats or tun N. Y. Acapemy or Screncrs, 
Woite IL; No, @3) Wino, 187s] 
AXIL—On the Jaw and Lingual Dentition of certain Costa 
fica Land Shells collected by Dr. Wititam M. Gass. 
BY W. G. BINNEY. 
(WITH PLATE XI. ) 
Read December 23d, 1878. 
Among the specimens of land shells collected in Costa Rica 
by the lamented Dr. Gabb, were several preserved in spirits. 
These were subinitted tome by him. I have examined the jaw 
and lingual dentition, and here offer the results of my exam- 
ination. The original figures of the living animals, as drawn 
by Dr. Gabb, are also given, and his notes incorporated in the 
text. It will be seen that Dr. Gabb discovered two new 
genera. 
Velifera*, n. g. 
Animal f (pl. xi, fig. A), heliciform, blunt before, tapering behind , man- 
tle subcentral, thin, furnished with one or more { accessory processes 
which cover most of the shell : respiratory, anal, and generative orifices, —? : 
a distinct locomotive disk : longitudinal furrows above the margin of the 
foot, meeting over a simple, longitudinal mucus-pore (pl. xi, fig. D.) 
Shell (pl. xi, fig. B) imperforate, globose, very thin, polished; whorls few 
the last very large, scarcely falling at the aperture: aperture slightly oblique, 
large: peristome acute. 
Jaw with smooth anterior surface and beak-like projection to the cutting 
edge. 
Lingual membrane (pl. xi, fig. C) with the general arrangement of Zon- 
ites ; the first laterals have an inner side cutting point: marginals aculeate, — 
With side spur. 
Although this animal does not combine the characters of 
any described genus, it is related to several by its separate 
characters. It has the caudal mucus-pore, and the jaw, of 
Zonites; but differs in having an appendiculate mantle. In 
_ ~ Velum, a covering, a vail; fero. 
+ Animal heliciforme, antice obtusum, postice attenuatum, pallium tenue, 
subcentrale, appendiculatum, testam velans; apertura respiratoria, analis, 
et genitalis,—?; discus gressorius distinctus; porus mucosus caudalis. 
Testa imperforata, globosa, tenuis, nitens, paucispira, anfr. ultimus 
globosus; peristoma acutum, 
{As Dz. Gabb’s figure gives the left of the animal, it is impossible to 
describe these processes correctly, 
