PATELLA. LIMPET. Ml 
? 16. Patella Fissura. Slit Limpet. 
Lister, pi. 543. f. 28— Pennant , pi. 93. f. 3 — Da Costa, 
pi I. f. 4— Donovan , pi. 3. f. 2 —Dorset Cat. pi. 23. f. 4. 
Shell oblong, conic, brown or white, semitransparent, 
with strong regular longitudinal rib3 and transverse ones 
in the interstices, toothed round the margin, where on one 
side is a narrow* fissure or slit which sometimes reaches 
nearly half way up the shell: crown nearly central, pointed 
?.nd curved inwards, but hardly forming a single volution : 
length of the base half an inch j breadth and height about 
half as much. 
On most sandy coasts, v. v. 
C. JFith the crown perforated , 17 to 20. 
1J. Patella Apertura. Open Limpet. 
Montagu, pi. 13. f. 10. 
Shell oblong-oval, flattish, semitransparent, white with 
a few longitudinal brown streaks reaching halfway up from 
themargin, with strong longitudinal tubercled ribs crossed 
hy a few circular ridges : crown recurved, the point small 
and turning inwards so as occasionally to form a single vo¬ 
lution which is attached to the shell, and just below the 
commencement of the volution is a rhombic perforation ; 
inside smooth glossy, with the circumference oval, and 
toothed at the edge by the ribs : length nearly a quarter 
of an inch; height not half as much. 
On the western coasts: very rare. v. m. 
18. Patella Grrnca. Cancelled Limpet. Fig. 82. 
Utter, pi. 527- f- 2— Pennant , pi* 92. f. 3— Da Costa , 
pi. 1. f. 3— Dorset Cat. pi. 23. f. 3. 
Patella reticulata. Donovan , pi. 21. f. 3. 
Shell thick, opake, oblong-oval, very little conic, white 
or dull brown, with strong longitudinal ribs of unequal 
size, crossed by transverse ones, giving a rather tubercled 
ippearance to some of them: crown not much elevated, 
placed nearer to one end, truncate, and furnished with an 
oblong perforation; inside smooth, white, sometimes 
marked with brown or dull purple rays 5 the margin a little 
indented. 
