BRACHIOPODA. 



333 



Genus PROBOSCIDELLA, (Ehlert. 1887. 



1840. Productus, db Vbrkeiiil. Bull. Soc. Geol. de France, vol. vi, p. 259, pi. lii, fig-. 3. 



1841. Clavagella, Goldpdss. Petrefacta Germanije, vol. ii, p. 285, pi. clx, fig. 17. 



1841. Productus, von Bdch. Abhandl. der Kbnigl. Akad. dei' Wissensch. zu Berlin, Theil i, p. 40. 



1843. Productus, de Koninck. Descript. Animaux Fossiles du Terr. Carb. de Belgique, p. 11, fig. 4. 



1847. Prodtictus, de Koninck. Monog:-aphie du genre Productus, p. 62, pi. vi, fig. 4. 



1854. Productus, Norwood and Pkatten. Joui-n. Acad. Nat. Sci. Philadelphia, 2d Ser., vol. iii, p. 10. 



1861. Productits, Davidson. British Carb. Brachiopoda, ji. 163, pi. xxxiii, figs. 1-4. 



1880. Productus, Davidson. British Carb. Brachiopoda, SuppL, p. 311, pi. xxxvi, fig. 13. 



1887. Proboscidella, (Ebl^rt. In Fischer's Manuel de Conchyliologie; Brachiopodes, p. 1277. 



Diagnosis. " Valves very unequal ; the dorsal small, concave, operculiform ; 

 the ventral larger, convex, furnished with two lateral expansions which bend 

 downward to meet the margins of the dorsal valve, and an anterior expansion 

 which is produced forward into a long cylindrical tube, sometimes attaining 

 twice the length of the shell ; the suture appears on the dorsal side in the 

 median line. Sometimes instead of a single tube there is a double enrollment 

 resulting in two distinct tubes. The surface is ornamented by concentric plica- 

 tions, traversed by fine radiating ribs, which are flexuous and close together ; 

 the last plication, and the groove accompanying it, is sharper than the others 

 and marks the separation of the ventral valve, properly speaking, from its 

 lateral and anterior expansions upon which the concentric markings are rare, 

 faintly developed or wholly wanting, while the radiating striae are regularly 

 continued." (CEhlebt, loc. cit.) 



Carboniferous limestone. 



Type. Productus proboscideus, de Verneuil. 



Figs. .31-33. Productus (Proboscidella) proboscideus, de Verneuil. 

 After DE Koninck. 



