MYA. GAPER: 
97 
ten or twelve, very short, wrought with tubercled spiral 
ridges, between which are three or four series of crenate 
stride; the base spirally striate : aperture small, oval, end¬ 
ing in a slight canal: length an inch and a half $ breadth 
half an inch. 
In large shells the tubercles extend into long conic 
spines on the larger volution, and sometimes run together 
into a sharp spiral screw-like ridge. 
Weymouth, and northern coasts : very rare. 
26. Murexadversus. Reversed Rock-shell. 
Turbo reticulatus. Donovan, pi. 159. 
Turbo punctatus. Walker , f. 48. 
Shell reversed, tapering to a line point, opake, light- 
brown: spires ten or eleven, scarcely defined by the line 
of separation, with three rows of tubercles on each, the 
middle row of which is smaller than the rest: aperture 
oval, ending in a straight canal; the base with two or three 
smooth spiral ridges : length nearly half an inch; breadth 
hardly the eighth. 
♦ Western and Scotch coasts : very rare. 
2/. Mures minutissimus. Linn. Trans, iii. p. 65. 
Shell taper, transparent; spires five, with remote ribs, 
and spirally,striate; canal closed. 
Pembrokeshire coast : minute. 
MYA. GAPER. 
Shellwith two valves, generally open at one end : 
hinge with mostly a single broad thick spoon¬ 
shaped tooth, generally not inserted into the oppo¬ 
site valve, 
A. The teeth not inserted into the opposite valve , 1 to 17* 
B. The teeth locking into the opposite valve , 18 to 24. 
* 1. Myatruncata. Abrupt Gaper. 
Lister , pi. 428. f. 269 — Pennant, pi. 44 — Da Costa T 
pi. 16. f. 1— Linn. Trans . vi. pi. 14. f. 1, 2— Donovan, 
pi .92-Dorset Cat. pi. 3. f. 1— Wood, pi. \?.f. 1, 2. 
Shell oblong-oval, strong, broad, abruptly cut off at the 
n smaller 
