100 
MOLLUSCA. 
Bulla. 
Subdiscoidal; spire depressed, with four flattened volutions, 
with an indistinct carina at the base of each; body flat above, 
and carinated, convex beneath; callus, narrow, and rather ele¬ 
vated, and not so distinct as in the former species; surface with 
obscure stria?. 
Lias, Lyme Regis, Dorsetshire. 
3. Cochlicarina compressa —The Compressed Cochli- 
carina, pi. XLVII. fig. 7, 8. 
Helicina compressa . Sowerby, I. p.33, pi. 10, three middle 
figures. Fleming, p. 258. 
Subglobose, smooth, thick, and strong; spire slightly depres¬ 
sed ; superior portion of the body, and base of the volutions of 
the spire, carinated; base convex; callus broad; aperture some¬ 
what angular above. 
In Lias Limestone, Gloucestershire. 
4. Cochlicarina polita. —The Polished Cochlicarina, pi. 
XLVII. fig. 5, 6. 
Helicina polita. Sovverby, III. p. 153, pi. 285. Fleming, 
p. 258. 
Subrotund, smooth, polished; spire subconic, consisting of 
five volutions, subdepressed above, with a carina at their base, 
which continues along the superior portion of the body, and 
terminates in the outer lip; body separated from the spire by 
an impressed fillet, and finely rounded below, with a thin callus 
expanded half over the base ; aperture subquadrangular; upper 
parts with perversely arcuated lines of growth, which indicate a 
sinus in the right lip. 
In Marly Sandstone of the Lower Oolitic series at Cropredy. 
Genus LV11.— HELIX. — Linnams. 
Shell orbicular, thin, subglobose; body very large; 
spire short, and small in proportion to the body; aperture 
oblique; outer lip reflected, and interrupted by the bulg¬ 
ing of the body; columella confluent with the outer lip, 
and situate on the lower portion of the axis; destitute of 
an operculum. 
1. IIelix Gentii—G ent’s Helix, pi. XLVII. fig. 9, 10. 
Helix Gentii. Sowerby, II. p. 101, pi. 145. Fleming, p. 264. 
Subglobose, smooth; body large; spire small, consisting of 
three depressed volutions, the apex obtuse; superior portion of 
the body, and base of the volutions, provided with a spiral, 
narrow, hollow band, or sulcus; aperture elliptical, ample, 
much expanded; whole surface furnished with obscure, arcu¬ 
ated lines of growth, except in the sulcus, where they are more 
conspicuous. 
Greensand near Devizes. 
2. IIelix globosa. —The Globular Helix, pi. XLVII. fig. 
33, 34. 
Helixglobosus. Sowerby, II. p. 157, pi. 170. Fleming, p.264. 
Globular, slightly longer than broad; body very large; spire 
rather short, obtuse, consisting of three rather broad, slightly 
tumid, and gradually increasing volutions, with obscure, irregu¬ 
lar, spiral striae, and crossed by lines of growth ; aperture semi- 
lunate; outer lip slightly reflected; umbilicus concealed by the 
expanded glazing on the columellar lip. 
Young shells are somewhat depressed, provided with an umbilicus. 
Crag, Fresh Water formation, Isle of Wight. 
ORDER IV.—GASTEROPODA. 
Animals with the body straight, never spiral, nor 
totally enveloped in their shell; the foot, or disc, situated 
under the belly, united to the body nearly its whole 
length, and serving as an organ of locomotion. 
Grand-Division I.—PNEUMOBRANCHLE. 
Branchiae in the form of a vascular net, or the wall of 
a particular cavity, opening by a hole, which the animal 
contracts or dilates at pleasure. They respire air. 
FAMILY I.—BULLACEA. 
Shells greatly distended, and without any apparent 
columella. 
Genus I.—B TILL A. — Linnceus, 
Shell convolute, oval, with a depression above instead 
of a spire; aperture longitudinal, as long, or longer than 
the convolutions, straitened above, and expanded beneath, 
where it is effuse; outer lip thin; columellar lip generally 
reflected, with a coating of shelly matter. 
1. Bulla convoluta. —The Convoluted Bulla, pi. XLVII. 
fig. 11, 12. 
Bulla convoluta . Brocchi, p.277, pi. 1, fig. 7. Sowerby, 
V. p. 95, pi. 464, fig. 1. Fleming, p. 295. 
Cylindrical, smooth ; aperture narrow, linear, widened near 
the base; vertex obtuse, subtruncated, perforated, exposing a 
deep umbilicus. 
In the Crag at Ipswich. 
2. Bulla elliptica. —The Elliptical Bulla, pi. XLVII. 
fig. 13, 14. 
Bulla elliptica . Sowerby, V. p. 96, pi. 464, fig. 6. Fle¬ 
ming, p. 295. 
Regularly elliptical, elongated, rounded at both extremities; 
vertex deeply perforated; aperture linear, wider below than 
above; surface with fine, regular, transverse stria?, somewhat 
wider near the base. Three lines long. 
London Clay, Barton Cliff. 
3. Bulla elongata. —The Elongated Bulla, pi. XLVII. 
fig. 19. 
Bulla elongata. Phillips, I. p. 102, pi. 4, fig. 7. 
Elongated, smooth, narrow, and umbilicated above, wide 
beneath ; outer lip thin, and somewhat hollow in the centre; 
aperture contracted above, rounded, and wide beneath. 
Coralline Oolite, in the lower beds at Seamar, Malton, and 
Scarborough. 
4. Bulla filosa.—T he Thready Bulla, pi. XLVII. fig. 20. 
BullaJilosa. Sowerby, V. p. 97» pi. 464, fig. 4. Fleming, 
p. 295. 
Elliptical; aperture narrow above, wide, and rounded beneath; 
outer lip considerably expanded; surface covered with numerous, 
regular, transverse striae. 
Distinguished from the preceding by its expanded lip and numerous 
striae. 
