230 BRITISH CARBONIFEROUS BRACHIOPODA. 



Productus Koninckianus, Be Verneuil. Plate LIII, fig. 7. 



Productus cancrini, Be Koninck. Descript. des Anim. foss. du Terr. Carb. de Belgique, 

 p. 179, pi. ix, fig. 3, 1843 (not of De Verneuil and De Keyserling). 



— Koninckianus, Be Verneuil. Russia and the Ural Mount., vol. ii, pp. 253 and 



274, 1845. 



— — Be Keyserling. Keise in das Petschora Land, p. 203, pi. iv, 



fig. 4, 1846. 



— spinulosus, Be Koninck. Mon. du genre Productus, pi. xi, fig. 2, 1847 (not 



of Sowerby). 



Sp. Char. Shell longer than wide, posteriorly rounded, broadest anteriorly ; ventral 

 valve evenly convex, without sinus ; beak gibbous, much elevated and incurved, but not 

 overlying the hinge line, which is less than the greatest width of the shell ; ears very small, 

 with two or three wrinkles ; surface covered with numerous undulating regular, thread- 

 like striae, which increase from the interpolation of smaller striae at variable distances from 

 the beak, and which are interrupted at short intervals by small tubercules, disposed pretty 

 regularly in quincunx, and giving rise to slender spines. Ventral valve concave, following 

 the curves of the opposite one. Dimensions variable. 

 Length 9, width 8 lines. 



Obs. This pretty little species has been taken for Sowerby's P. spinulosus by Prof, 

 de Koninck, but from which it is completely distinct, Sowerby's shell not being longitu- 

 dinally striated, as is the case with the form under description. It differs also in shape 

 from P. spinulosus, which is usually transverse, while P. Koninckianus is generally slightly 

 longer than broad ; and, lastly, it differs again by the profile curve presented by the larger 

 or ventral valve. It is also distinct from Productus Cancrini. Prof, de Koninck observes 

 that apart from the arrangement of the spines it is a complete miniature of P. Cora, and 

 that it is distinguishable from P. arcuarius by the absence of the transverse concentric 

 furrow which divides the ventral valve of the last-named shell into two distinct portions. 



The discovery of this species in the Lower Scar Limestone of Settle, in Yorkshire, is 

 due to Mr. Burrow, and I am not acquainted with any other British locality. In Belgium 

 it is very rare in the limestone of Vise, and has been found by Count Keyserling in 

 Carboniferous Limestone on the banks of the Soiwa in the Petschora, Russia. 



Productus undiferus, De Koninck. Plate LIII, figs. 5, 6. 



Productus spinulosus, Be Koninck. Descript. des Anim. foss. du Terrain Carb. de 



Belgique, p. 183 (partim), pi. x, fig. 4, 1843 (not P. spinulosus, 

 Sow.). 

 — undiferus, Be Koninck. Monogragliie du genre Productus, pi. v, fig. 4, and 



pi. xi, fig. 5, 1847. 



