43 
jocular, suhirregular, nearly flat, slightly convex above, 
s 1 J? a small apex near the middle; margin acute; inner 
Cp ace rather concave, with a callous disk, depressed in the 
'“.K with a smooth border) all the recognized species of 
hlc h are Indian. 
CALYPTRICIANA. 
Shell always external, covering the animal. 
EMARGINULA. 
GENERIC CHARACTER: Shell shieldlike, conical, 
* ^ er tex inclined, cavity simple, the hinder margin notched. 
PISSURA. Patella F. Turt. Lin. Pen. Brit. Zo., 
4, pi. 90, erroneously marked 151. Ment. Test, 
vol. 1 , p. 490, E. F. Flem. Brit. An,, p. 365. 
Aot uncommon, from deep water. 
e FISSURELLA. 
GENERIC CHARACTER: Shell shield-like or depressed 
c °nical, concave below ; without a spire, and perforated 
* -j^ *he top ; aperture oblong. 
*• GRAECA. Patella G. Turt. Lin. Pen. Brit. Zo., 
p°l- 4, pi. 89, fig. 153. Mont. Test. Brit., vol. 2. p. 492. 
G. Flem. Brit. An., p. 364. Rare. I have obtained it 
r °ni near Looe, at Falmouth, and near the Land’s-end but 
with the animal. Mr. Forbes (Fauna Monensis) says 
oat their habit is, to attach themselves to Pectens, in 
j, ee p-water. 
• APERTURA. Patella Fissurella. Turt. Lin. P. 
APertura Mont. Test. Brit., vol. 2, p. 492, pi. 13, fig. 10 . 
» VJ em - Brit. An., p. 3G4. Very rare. 
H? AiUBECULA. Flem. Brit. An., p. 365, from Dr. 
1 J rton; who obtained it near the Land’s-end ; from whence 
p S ° I procured a few specimens. It has been found at 
° r ran bv Mr. Peach. 
G PILEOPSIS. 
^ERlc CHARACTER: Shell obliquely conical, cur- 
a forward ; the top bent, approaching to a spiral ; 
Pertn re somewhat oval ; anterior margin shortest, acute, 
ID g in a slight sinus; hinder margin larger, round ; a 
,1 6 l hened, arched, transverse muscular impression under 
* p e hinder border. 
•UUNGARICUS. Patella H. Turt. Lin. Pen. Brit. 
°‘> vol. 4 , p], go, fig. 147. Borlase’s Nat. Hist. Corn., 
’ ^ 8 , fig. 4. P. Ungarica. Mont. Test. Brit., vol. 2, 
Co C a pulus H. Flem. Brit. An., p. 363. Not un- 
of In tnon on the Pinna from deep water; and one specimen 
Us size had its border so curved to accommodate 
e to the irregularity of the surface, as to show that it 
