1 
92 MUREX. ROCK-SHELL. 
aperture narrow-oblong, contracting a little at the canal, 
which is moderately long and nearly straight; outer-lip 
thickened by a rib at the back ; inner-lip plain: length half 
an inch ; breadth an eighth or more. 
Western coasts, and Dublin bay. v. tn. 
10. Murex Nebula. Gauze Rock-shell. 
Montagu , pi. 15. f. 6— Pennant , pi. 82. f. 7— Dorset Cat. 
pi. 14. f. 16. 
Shell slender, tapering to a line point: spires eight or 
nine, scarcely raised, and separated by a very tine line, with 
eight or nine longitudinal ribs, and crossed transversely in 
the interstices by very fine faint lines: color yellowish- 
white or brownish, sometimes pale rose-color, with the 
transverse stricc white: aperture oval-oblong, narrow; 
outer-lip thin and plain; inner-Jip a little rugged on the 
outside ; canal rather short, turning a little to one side: 
length half an inch ; breadth two tenths. 
On many fine sandy shores, v. v. 
11. Murex septangularis. Septangular Rock-shell. 
Montagu, pi. 9. f. 5— Donovan, 179. f. 4. 
Shell strong, taper, pale brown, ratherglossy; spires seven 
pr eight, with seven longitudinal ribs which are scarcely 
interrupted by the line of separation, the spaces between 
the ribs smooth and but slightly concave, giving the sheila 
septangular appearance; outer-lip thin, contracted to an i 
angle at the upper part, where the margin is a little in¬ 
dented ; pillar-lip a little folded back : length half an inch, - 
or rather more; breadth a quarter. 
Western coasts, and Dublin bay: rare. v. m. 
12. Murex costatus. Ribbed Rock-shell. 
Pennant, pi. 82. f. 2 —Da Costa , pi. 8 . f. 4—Donovan. ' 
pi. 91— Dorset Cat . pi. 14. f. 4. ^ 
Shell oblong, taper, rather glossy: spires six, flat and : 
divided by the line of separation only, with seven or eio’nt , 
elevated ribs, placed rather remotely, and not striate trans- 
versely: color chocolate-brown, with often white bands, or 
entirely white at the base; sometimes yellowish-white with | 
£ dark brown band or two: aperture very narrow, not 
much 
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