LAMELLIBRANCHIATA. | DEVONIAN MOLLUSCA. 393 
AVICULOPECTEN PECTINOIDES (Sow. Sp.) 
Ref. and Syn. = Avicula Pectinoides Sow. Geol. Trans. 2nd Series, Vol. V. t. 54. f. 2. 
¢= Meleagrina rigida M°Coy, Synop. Carb. Foss. Irel. t. 13. f. 16. 
Sp. Ch.—Rotundato-quadrate ; valves nearly flat, posterior ear very large, undefined, equalling or slightly 
passing the posterior margin in length; posterior margin slightly sigmoid, forming a short acute termination of 
the hinge-line ; entire surface of the body of the shell and posterior ear radiated with subequal, obtuse, sharply- 
defined, narrow, rugged ridges, separated by flat smooth spaces, equalling or slightly exceeding them in width 
(at one inch from the beak) ; in the middle of the shell five or six ridges in the space of three lines, at one inch 
and half from the beak, and at two inches three or four in the same space. Average width from two to two 
and half inches. 
In general outline, and the disposition, and general character of the ridging, this species agrees nearly 
with the Aviculopecten granosus and A. plicatus (Sow. Sp.), from which however it is clearly distinguished by 
the greater size, the fewer ribs in a given space on all parts of the shell, by their more near equality in size, and 
their wide flat interspaces ; this latter character, however, is considerably exaggerated in Mr Sowerby’s figure, 
as may be seen from the above accurate measurements taken from his original specimen. None of the ad- 
ditional fragments which I have seen shew any trace of the regular concentric ridging of Goldfuss’s figure of 
A, Neptuni, which is therefore, as Sowerby suggests, probably distinct. I strongly suspect, after seeing the 
difference between Mr Sowerby’s type-specimen and his figure, that the Meleagrina (Aviculopecten) rigida of 
my volume on the carboniferous fossils of Ireland from the carboniferous slate of that country, should now 
be united therewith; in that case the anterior ear would be square, undefined, and ridged like the rest of 
the shell. 
Position and Locality—Rare in the soft olive slate of S. Petherwin, Cornwall, 
AVICULOPECTEN TRANSVERSUS (Sow. Sp.) 
Ref. and Syn. = Pecten transversus Sow. Geol. Trans. 2nd Series, Vol. V. t. 53. f. 3. 
Sp. Ch.—Subelliptical, compressed ; anterior ear small, subtrigonal ; posterior ear larger, faleate; valves 
flattened, slightly convex towards the beaks; surface radiated with obtusely angular ridge-like groups, com- 
posed each of three angular subequal strize, without distinct interspaces (about seven in two lines in middle of 
ventral margin, at nine lines from the beak), all crossed by sharp scaly lines of growth, rendering the angles 
spinulose ; ridging of the ears irregular. Length from anterior to posterior margin parallel with the hinge 
about one inch five lines, proportional length from beak to opposite margin 7. 
The proposed reference of this shell to the Pterinea radiata (Gold.) by Phillips, d’Orbigny, Bronn, &c., 
I find, on examining the original specimen, to be incorrect, as the British species has radiated ears, and much 
more numerous and finer ribs of nearly equal size; besides their remarkable regularity of grouping. 
Position and Locality.—Rare in the slate of S. Petherwin, Cornwall. 
Genus. DOLABRA (AM'Coy). See page 269. 
DoLaBRA ANGUSTA (Sow. Sp.) 
Ref. and Syn. = Cuculleea angusta Sow. Geol. Trans. 2nd Series, Vol. V. t. 53. f. 25. 
Sp. Ch.—Subquadrate ; length and width nearly equal; moderately gibbous, most so towards the beaks, 
gradually becoming depressed towards the margins; beaks a little on the anterior side of the middle, large, 
approxmiate ; diagonal ridge obtusely rounded, only distinct near the beaks; posterior slope flattened, posterior 
margin straight, truncated, nearly at right angles with the hinge-line and ventral margin, which latter is slightly 
convex and subparallel with the hinge; anterior end broadly rounded, posterior cardinal tooth in left valve 
usually strongly marked, nearly as long as the hinge, from which it slightly declines, bifid in the right valve. 
Length from anterior to posterior margins one inch one line, width from beak to opposite ventral margin * 
[rasc. 11.] 3E 
