182 
THE GEOLOGIST. 
XXXIX. — Productus spinulosus. J. Sowerby. PI. iv., figs. 23-24. 
rroditdus spinnlosiia. J. Sowerby, Min. Con., vol. i., p. 151, pi. Ixviii., fig. 3, 
1814. De Koninck, Mouograpliic da Genre Productus, pi. xi., fig. 2. 
This shell is transversely semicircular, the hingc-liue being nearly as long as 
the greatest width of the shell. The ventral valve is regularly convex, and 
evenly arched, without sinus; the beak incurved, and not overlying the hinge- 
line, except quite at its attenuated extremity. The ears arc flattened, with a 
few concentric wrinkles. The dorsal valve, which is very concave, follows the 
curves of the opposite one. Externally the surface is covered with numerous 
short spines, arranged in quincunx, and generally about half a line or so apart : 
they originate from a small slightly elongated tubercle, wliich aioue is usually 
])rcseut in the fossil. The interior arrangements are unknown, and the shcU 
does not ap|)ear to have ever attahicd large proportions, some Scottish 
examples that have come under my observation having measured seven and a- 
half lines in Icngtli by nine in width ; and it is always easily distinguished 
from other Scottish species of Productus by its shape, as well as by the peculiar 
quincunx arrangements of its slender spines. 
In Lanarkshire P. xpiiiiiloxii.t has been collected at Nellfield and Hill Head, 
at three hundred and seventy-five fathoms below the " Ell coal ;" also Brock- 
ley, near Lcsmahago. In Ayrsliirc, at West Eroadsteme and Auchenskeigh, 
near Dairy. Prof. Fleming's original specimen, which is figured on our plate, 
was from Linlithgowshire. In Haddingtonshire, at Cat Craig, near Dunbar. 
XL. — PaoDUCTUS MESOLOBUS. Phillips. PI. ii., fig. 21. 
Prodncta we.ioloha. Phillips' Geol. of Yorkshire, vol. ii., p. 215, pi. vii., figs. 
12-13, 1S3G, and De Kouinck's Mon. da Genre Productus, pi. xvii., fig. 2. 
This shell is transverse, with a very long straight hinge-line. The auriculate 
expansions project and form attenuated cardinal extremities, while the lateral 
margins are rounded, and straight or undulating in front. The ventral valve 
is very gibbous at the beak, aud sometimes genieulated towards the front, with 
a wide flattened or slightly concave sinus, interrupted in the middle by a 
narrow median rib : on either side of the sinus a similar ridge or rib is present, 
and another intervenes between these and the cardinal angles. On the five 
ridges may be seen a few tubercles, from which projected small tubular spines. 
The beak is of moderate size, and not overlying the hinge-line, except quite at 
its attenuated extremity. The dorsal valve is concave, with a narrow median 
groove and two slightly marked lateral ones : concentric Unes of growth 
are observable upon both valves. The interior of the valves are unknown ; 
and the largest Scottish example that has come under my observation did not 
exceed eight lines in length by thirteen in widtli, but the shell has elsewhere 
attained large proiwrtions, and can always be easily recognized on account of 
its peculiar shape and character. 
At Praidwood, in Lanarkshire, it has been found at three hundred and 
seventy-five fathom below the "Ell coal." At Brockley, near Lesmahago. In 
Stirlingshire, in the Glarat lime works or Cam])sie main limestone. It does 
not appear to be a very common species in Scotland. 
XLI. — Productus pustulosus. Philli])s. PI. iv., fig. 19. 
Prodiirta pustulosa. Phillip's Geol. of Yorkshire, vol. ii., pi. vii., fig. 15. 183G. 
Tliis sheU is rotnndato-quadrate, rather wider than long, with a straight 
hinge-line, somewhat shorter than the greatest width of the shell. The ventral 
valve is gibbous, with a wide shallow mesial sinus ; the beak being moderately 
developed and incurved, but not overlying the hinge-liuc ; the auriculate ex- 
