L26 CARBONIFEROUS LAMBLLIBRANCHIATA. 



Pachypteeia nobilissima, de Koninck, sp., 1851. Plate XXV, fig. 7. 



Osteea nobilissima, de Koninck, 1851. Descr. Aniin. Foss. Terr. Carb. Belg., 



Suppl., p. 680, pi. lvii, figs. 1, a, b, c. 



Pachtpteria nobilissima, de Koninck, 1885. Ann. Mus. Boy. d'Hist. Nat. Belg., 



tome xi, p. 201, pi. xl, fig. 1. 



Specific Characters. — Shell of medium size, flattened, irregular, somewhat 

 twisted on itself, suboval, slightly oblique. Hinge-line straight. Umbones incon- 

 spicuous. The anterior border more convex than the posterior, the inferior 

 somewhat irregularly convex. 



Interior. — The adductor muscle-scar single, large; surrounded by a subcircular 

 crest. 



Exterior. — The surface is ornamented with fine, close, lamelliform, concentric 

 lines of growth. 



Dimensions. — PI. XXV, fig. 7, a right valve, measures — 



Antero-posteriorly . . . .29 mm. 



Dorso-ventrally . . . .35 mm. 



Localities. — England : the Carboniferous Limestone of Park Hill, Derbyshire, 

 and Hill Bolton, Yorkshire. 



Observations. — The specimen from Park Hill (PI. XXV, fig. 7) is evidently a 

 young example. It shows the interior of the right valve, and is not very well 

 preserved. The specimen I obtained from Hill Bolton was unfortunately fractured, 

 and I have only the lower half of the valve, which includes half of the adductor 

 muscle-scar. It is part of a much larger shell measuring about GO mm. trans- 

 versely. P. nobilissima must be very rare, as I have only met with these two 

 examples in Great Britain, unless the Anomia anliqua of M'Coy represents the 

 species, though I incline to the view that the type was a valve of some species of 

 Productus. De Koninck's specimens were obtained from the Limestone of Vise. 



Pal koi, ima Buohiana, de Ko7iincJc,s-p., 1844. Plate XIX, tigs. 13 — 10. 



Avicula tumida, de Koninck, 1842. Descr. Anim. Foss. Terr. Carb. Belg., p. 138, 



pi. i, fig. 12 ; pi. iii, fig. 14. 



— l^vigata, de Koninck, 1842. Ibid., p. 137, pi. ii, fig. 10 ; pi. iii, fig. 19 ; 



pi. iv, figs. 4, 9. 



— Buchiana. de Koninck, 1814. Ibid., p. 634. 



