MUREX* ROCK-SHELL. 
95 
purple, marked by the outei*-ribs; pillar striate transversely 
in an oblique direction, to the end of the canal: length five- 
eighths of an inch j breadth a quarter. 
Salcombe bay, and Dublin bay : rare. v. in. 
Variety , with a notch on the upper angle of the outer- 
lip, like that on M. gracilis. 
19. Murex muricatus. Prickly Rock-shell. 
Montagu, pi. 9. f. 2. 
Shell strong, rough, taper, white with a reddish or 
greenish tinge, often covered with an orange-red skin : 
Spires six or seven, swelling and deeply defined, rather 
fattened at their tops, with about ten prominent ribs, and 
Crossed by very strong raised lines, giving it a tubercled 
appearance: aperture roundish, ending in a long straight 
narrow canal, which is nearly smooth, and with the aper¬ 
ture almost as long as the rest of the shell ; outer-lip 
spread, toothed at the edge, and slightly crenate within ; 
pillar smooth: length more than half an inch ; breadth not 
a quarter. 
Western coasts, and Dublin bay. v. m. 
I 20. Murex Bamffius. Scotch Rock-shell. 
Donovan, pi. 169. f. 1— Pennant , pi. 82. f. 5. 
Shell conic, tapering to a fine point, yellowish-white : 
spires six, swelling and rounded, with from twelve to twenty 
much raised ribs, which are sometimes spread into thin 
sharp longitudinal foliations, sometimes flat and irregular, 
and often curved towards the aperture, not strinte trans¬ 
versely: aperture roundish, suddenly sloping at the outer 
;r.d lower angle into a rather straight and elongated canal ; 
the outer-lip thin: pillar rugged, with an indentation near 
the canal : length three-quarters of an inch ; breadth more 
tbn a quarter. The young shells are often rufous-brown. 
Scotch and western coasts, Dublin hay : rare. v. 
( 
\ 
^ 21. Murex Gyrinus. Screw Rock-shell. 
Laskey, IFern. Soc. i. pi. 8. f. 10. 
Shell strong, conic, short, tumid, brown: spires four, 
regularly covered with dark cliesnut turbercles, eight rows 
m the larger volutions, including the canal, and three 
row? 
