PRODUCTUS. 141 



Product^ giganteus, Martin. Plate XXXVII, figs. 1—4 ; Plate XXXVIII, fig. I ; 



Plate XXXIX, figs. 1—5 ; Plate XL, figs. 1—3. 



ANOMlTES giganteus, Martin. Petrif. Derb., pi. xv, fig. 1, 1809. 



— crassus, Martin. lb., pi. xvi, fig. 2, 1809. 

 Productus giganteus, J. Sow. Min. Con., vol. iv, pi. 320, Jan., 1822. 



— hemispii.ericus, J. Sow. lb., pi. 56 1, 182/. 

 Pkoducta gigantea, Phillips. Geol. of York., pi. viii, fig. 5, 1836. 



— aurita, Phillips. lb., pi. vii, fig. 6, 1836. 



— Edelburgensis, Phillips. lb., pi. vii, fig. 5, 1836. 



Leptcena variabilis, Fischer. Oryct. du Gouv. de Moscou, p. 144, pi. xxi, 1837. 

 Productus gigas oder giganteus, Von Buch. Abhandl. der Konigl. Akad. der 

 Wissens. zu Berlin, aus dem Jabre, p. 19, 1841. 



— comoides, Von Buch. lb., pi. i, figs. 1 — 3 (not Sow.). 



Producta hemisphverica, D'Archiac and De Vern. Trans, of the Geol. Soc. of 



London, 2d series, vol. vi, p. 397, 1842. 

 Productus giganteus, De Koninck. Animaux Foss. des Terr. Carb. de Belgique, 



pi. vii, fig. 1, 1843. 



— comoides, De Koninck. lb., pi. vii bis, fig. 1 (not Sow). 



Leptosna maxima, M'Coy. A Synopsis of the Characters of the Carb. Limest. of 



Ireland, pi. xix, fig. 12, 1844. 

 Productus striatus, E. Roberts. Atlas Geologique des Voyages en Scandinavie et de 

 la Commission Scientifique du Nord, pi. xx, fig. K, 1845 

 (non Fischer). 



— giganteus, De Verneuil. Russia and the Ural Mount., vol. ii, pi. xvi, fig. 



12, and pi. xvii, fig. 2, 1845; and P. Edelburgensis, ib., 

 pi. xviii, fig. 2. 



— — De Koninck. Mon. du genre Productus, pi. ii, fig. 1 ; pi. iii, 



fig 1 ; pi. iv, fig. 1 ; and pi. ix, fig. 8, 1847. 

 — M'Coy. British Palaeozoic Fossils, p. 463, 1855. 



— — Dav. The Geologist, vol. ii, pi. iii, 1859; and Scottish Carb. 



Mon., pi. v, figs. 1—4, 1861. 



Spec. Char. Shell large, varying in shape and striation according to age and specimen ; 

 somewhat transversely oval; hinge-line straight, exceeding the width of the shell, and 

 sometimes (though not commonly) possessing a narrow rudimentary hinge area in the 

 larger valve. Ventral valve greatly thickened, especially towards the middle, less so at the 

 beak, and near the margin ; more or less gibbous, and often much dilated at the ears, 

 which are semi-cylindrically enrolled, and more or less defined. Beak moderately developed, 

 incurved, and overhanging the hinge-line near its extremity only. Exterior evenly convex, 

 or more or less deeply and irregularly furrowed, the surface being covered with a vast 

 number of longitudinal flexuous striae, which vary according to age and specimen, three or 

 more usually occupying the width of a line towards the middle or margin of the valves. 

 The striae are also at times confluent, bifurcating, or suddenly disappearing and again re- 

 appearing and increasing in number towards the margin of the valve. They are likewise 



