176 BRITISH CARBONIFEROUS BRACHIOPODA. 



losus, De Koninck (but not of Sow.), is likewise a different species, for in addition to the 

 tubercules, the shell is represented as being finely longitudinally striated, a character never 

 observable in the many British examples of P.spinulosus, Sow., and P. granulosus, Phillips, 

 that have come under my observation. I have never yet seen a well-preserved exterior of 

 the smaller valve, but believe it to have possessed spines. In England P. spinulosus occurs 

 in the Carboniferous limestone of Bollancl ; Settle, in Yorkshire ; the Isle of Man, and in 

 several Derbyshire localities. In Scotland it has been collected at Nellfield and Hillhead 

 at 375 fathoms below "Ell Coal;" occurs likewise at Brockley, near Lesmahago, in 

 Lanarkshire. In Ayrshire, at West Broadstone and Auchenskeigh, near Dairy. At Cat- 

 Craig, near Dunbar, &c. In Ireland Mr. Kelly mentions Knockinny, Killukin, Millecent, 

 and I possess a specimen from Little Island, near Cork, for which I am indebted to Mr. 

 J. Wright. On the Continent it occurs at Vise, in Belgium, and has been found in 

 Russia. 



Productus plicatilis, /. Sow. PI. XXXI, figs. 3 — 5. 



Productus plicatilis, J. Sowerby. Min. Conch., pi. -159, fig. 2, July, 1823. 



— — Phillips. Geol. of York., vol. ii, pi. viii, fig. 4, 1836. 



Leptcena polymokpiia, Muenster. Verzeichniss der in der Kreis-Natur. Samml. zu Bayr. 



befindl. Petref., p. 45, 1840 (according to Prof, de Koninck). 

 Productus plicatilis, De Kon. Desc. des Anim. foss. du Terr. Carb. de Belgique, pi. xii, 



fig. 7, 1843 ; and Monographic du genre Productus, pi. v, fig. 6, 



1836. 



— M'Coy. British Pal. Foss., p. 168, 18.35. 



Spec. Char. Shell thin, transversely oblong, slightly indented in front; hinge-line 

 about as long as the greatest width of the shell ; ventral valve gibbous, and more or less 

 o-eniculated ; the visceral disc is semicircular and very slightly convex, while the anterior 

 prolongation is abruptly arched ; a median depiession or sinus commences likewise at 

 a short distance from the beak and extends to the front. Beak small, not overlying the 

 hino-e-line ; ears flattened. Exteriorly, the visceral disc or posterior half of the valve 

 is traversed by numerous regular or irregular, undulating, concentric wrinkles, while the 

 entire surface is covered with fine, thread-like, longitudinal strisc. Spines long, slender, few 

 in number, and rising here and there from the surface of the valve. Dorsal valve 

 concave, with a small mesial elevation or fold towards the front. Sculpture similar to that 

 of the opposite valve. Dimensions variable ; two examples have measured — 



Length 16, width 23, greatest depth between valves 7 lines. 

 „ 10, ,, 13, „ ,, 4 ,, 



Obs. This Productus is well distinguished from its congeners both by shape and 

 sculpture. It bears some slight resemblance to Strophomena analoga, but (as justly 

 observed by Profrs. de Koninck and M'Coy) does not possess the area of the last-named 

 species, and its interior details arc those of Productus, as may be seen by a glance at fig. 5 



