DAVIDSON — SCOTTISH CARBONIFEROUS BRACIIIOPODA. 
113 
sliirc it occurs in the Mill Burn beds, and in the Campsic main-limcstonc. In 
Dumbartonsliii-e, in the Castlccary limestone. 
XXXIII. — PiioDXJCTUS scABiucuLUs. Martiu. PI. iv., fig. 18. 
Anomites scahricidiiK, Martin, Petrif. Derb., pi. xxxvi., fig. 5, 1809. Productus, 
Sowerby, Min. Con., vol. i., pi. clvii., pi. Ixix., fig. 1. 
This shell is marginally rotundaic-quadrate, and somewhat wider than long, 
the ventral valve being convex, with small flattened auriealate expansions, and 
a wide, but slightly deepened mesial depression, or sinus ; the liiuge-Kne is 
cither shorter, or as loug as the width of the shell, while the dorsal valve 
becomes slightly concave, with a small median elevation, or fold, apparent only 
in the viciuity of the frontal margin. The siuface of the larger valve is closely 
covered with numerous subregidar striae swelling out at close intervals in the 
shape of oblong tubercles, arranged somewhat irregularly in quincunx, and 
from which project short curved spines ; the valves are likewise at times feebly 
concentrically wrinkled, aud the surface of the dorsal valve is marked with 
uunierous small elongate, oval, tubercle-pits. 
I am not acquainted with any good interiors of this species ; all I know of 
the dorsal valve is derived from an uiternal east in ironstone, from Jock's Burn, 
in the parish of Carluke, and which shows that the cardinal process was bi- 
lobed, and that a small median ridge extended from its base to a little more 
than half the length of the slieil, the muscular and reniform impressions were 
very faintly nuirked, but appear to be similar to those of Productus pundatm. 
The largest Scottish examples with wliich I am acquainted measured fifteen 
lines in length by sixteen in width, but the shell has attained much larger 
dimensions in the neigbourhood of Dairy. 
P. scabriridus is plentiful in ironstone, at Jock's Bum, in Lanarkshire, at 
tlu'ce hundi'cd fathoms below the " Ell coal," three hundred and seventy-five at 
Braidwood and Hill Head, in the parish of Carluke, at Brockley, near Lesma- 
liago, and Robroystou and Moodies Burn north of Glasgow. In Stirlingshii-e it 
occurs in several stages, such as the Craigenglen beds, Campsie main-hmestone 
and ironstone, and Corrie Burn. In Benfrewshire, at Barrhead; Howood, near 
Paisley ; and Arden-quarry, TlionJiebauk. in Dumbartonshire at Castlccary. 
In Ayrshii-e, at Auehenskeigh, Dairy ; and West Broadstoue, Beith. It has 
also been found in Fifeshii-e aud iu the Lothians. 
XXXIV. — ^Productus punctatus. Martin. PI. iv., fig. 20-22. 
Anomites pwndatit.i, Martin, Petrif. Derb., p. 8, pi. xxxvii., fig. 6., 1809. Pro- 
dmtus, De Koninck, Monograpliie du Gem-e Productus, pi. xii., fig. 2 = P. 
elegans, M'Coy, etc. 
The shells of wliich this species is composed vary somewhat in shape from 
being transverse, or slightly elongated; aU are, however, more or less 
rotundate-quadrate, with a hinge-line shorter than the greatest width of the shell, 
the aurieulate expansions being flattened, but not always clearly defined. The 
ventral valve is moderately convex, with a wide longitudinal shuis, commencing 
at a short distance from the extremity of the beak, this last being small and 
incurved. The dorsal valve is but moderately concave, ^vith a very slight 
mesial elevation, wliich commences at about the middle of the valve and ex- 
tends to the front. The surface of the valves are externally covered with 
ninneroxTs sub-regular concentric bands, or ridges of growth, which increase in 
number aud breadth as they recede from the extremity of the beak aud hinge- 
line, but in very adult shcUs they again become closer and closer as they ap- 
proach the margin. These bands (m the ventral valve) are slightly raised to- 
wards their lower margin, and are abruptly separated from each other by a narrow 
VOL. III. p 
