L66 BRITISH CARBONIFEROUS BRACHIOPODA. 



The flattened border is nearly one third of the entire length of the valve. 



(Ms. This elegant shell appears rare in British Carboniferous rocks, but is easily 

 distinguished from other forms of the genus by shape and sculpture, as well as by the 

 flattened, ribbed border which encircles the valves. In England it has been found by Mr. 

 Burrow in the Calcareous limestone of Settle, in Yorkshire, by the Rev. T. G. dimming 

 in the Isle of Man, while in Ireland it occurs in the Calcareous limestone of Kildare. 

 On the Continent it is not very common at Vise, in Belgium. 



Productus actjleatus, Martin. PI. XXXIII, figs. 16 — 20. 



Anomites aculeatus, Martin. Petrif. Derbiensis, p. 8, pi. xxxvii, figs. 9, 10, 1809, 



(not Schlotheim). 

 Productus aculeatus, Sow. Min. Con., tab. lxviii, fig. 4, Oct., 1814. 

 Producta laxispina, Phillips. Geol. of York., pi. viii, fig. 13, 1836. 

 Productus spinulosa, Phillips. lb., vol. ii, pi. vii, fig. 14 (not of Sow.), 1836. 



— gryphoides, De Koninck. Desc. des Anim. foss. du Terrain Carb. de la 



Belgique, pi. ix, fig. 1, and pi. xii, fig. 12, 1843 (?) 

 aculeatus, De Koninck. Mon. du genre Productus, pi. xvi, fig. 6, 1847. 



— — M'Coy. British Palaeozoic Fossils, p. 458, 1855. 



Dav. Mon. of Scottish Carb. Brach., pi. ii, fig. 20, 1860. 



Spec. Char. Shell of moderate dimensions, ovate or semicircular, slightly transverse 

 or elongated ; hinge-line less than the width of the shell. Ventral valve regularly vaulted, 

 gibbous, without sinus ; beak much incurved and overlying the hinge-line at its attenuated 

 extremity ; auriculate expansions small and thin. Surface in the young shell covered with 

 a variable number of irregularly scattered, elongated tubercules, from which project small, 

 curved spines, but with age the tubercules are at times so close and elongated on the 

 anterior half of the valve that they become transformed into longitudinal ribs ; the surface 

 is moreover intersected by regular or undulating laminar, concentric lines. Dorsal valve 

 very concave, following closely the curves of the opposite one, and similarly ornamented. 

 Interior unknown. Dimensions variable ; three British examples have measured — 



Length 6, width 6|, lines (Martin's type). 

 11 19 



11 IS 



Obs. In general appearance this Productus varies considerably, according to age and 

 specimen, Martin's type (of which I have given a carefully enlarged representation) having 

 been described and drawn from a young shell, which was almost smooth, from the very few, 

 irregularly scattered, tubular spines which covered its surface j 1 but in other specimens, with 



1 Martin describes his species — "A fossil shell. Original an Anomia, imperforate, with one of the 

 valves concave, the other convex and gibbous. Hinge close, straight, but less extended than in most 

 other Anomita of the same division (Syst. G. B., ' Anomitse,' b, b). The convex valve prickly : the 



