26 
Umpretia.—Shell external, orbicular, sub-irregular, nearly flat, slightly convex above, 
white, with a small apex near the middle; margin acute, internal surface rather 
concave, having a callous disk, coloured, depressed in the centre, surrounded by 
a smooth border. 
Plate XIII. Fig. 15, 16. U. Indica. (Patella umbellata—Gmel.) 
CALYPTRACIANA. —7 GENERA. 
Shell always external, covering the animal. 
Parmornorvus.—Shell oblong, subparallelipipedal, slightly convex above, obtuse at the 
extremities, anteriorly channelled by a slight sinus, and having, towards the pos- 
terior part, a small pointed apex, inclined backwards; the lower surface slightly 
concave. 
Plate XIV. Fig. 1. P. australis. (Patella ambigua.—Chem.) 
(a) Under side of ditto. 
Emarcinuta.—Shell shield-like, conical; summit inclined; the cavity simple, having a 
notch or hollow cut on its posterior margin. 
Plate XIV. Fig. 2. E. rubra. 
FissurELLA.—Shell shield-like or depressed conical, concave below, perforated at the 
summit; without any spire; the perforation oval or oblong. 
Plate XIV. Fig. 3. F. pustula. (Patella pustulan—Chem.) 
Piteopsts.—Shell univalve, obliquely conical, anteriorly recurved; apex bent, almost spi- 
ral; aperture rounded-elliptical; the anterior margin shortest, acute, slightly si- 
nuated, the posterior largest and rounded: one elongated, arched, transverse mus- 
cular impression, situated under the posterior margin. 
Plate XIV. Fig 4. P. ungarica, (Patella ungarica.—Linn.) 
CaLypTr#A.—Shell conoidal, summit vertical, imperforate, subacute; base orbicular: 
the cavity furnished with a convolute lamina, or a spiral diaphragm. 
Plate XIV. Fig. 5. C. equestris. (Patella equestris—Linn.) 
(a) Under side of ditto. 
Crepiputa.—Shell ovate or oblong; the back almost always convex; concave under- 
neath; the spire very much inclined towards the margin: the aperture partly 
closed by a horizontal lamina. 
Plate XIV. Fig. 6 (a). C. fornicata. (Idem.—Linn.) 
(b). Under side of ditto. 
Ancy.us.—Shell thin, obliquely conical, the summit pointed, inclined backwards; aper- 
ture oval; the margin very simple. 
Plate XIV. Fig. 7. A. fluviatilis. (Patella fluviatilis.--Gmel.) 
