1878.] 17 [Rathbun. 



Lingula Rodriguezii Rathbun. 



Bull. ButFalo Soc. Nat. Sci., i, no. 4, p. 260, 1874. 



Found, with Discina lodensis, in the Devonian shales of Erere. 

 (Morgan Ex., 1870.) 

 Lingula Stauntoniana Rathbun. 



Bull. Buff. Soc. Nat. Sci., i, no. 4, p. 259, fig. 3, 1874. 



Moderately abundant in the Devonian shales of Erere, associated 

 with Discina lodensis, etc. (Morgan Ex., 1871; Geol. Coram., 1876.) 

 Lingula Gracana Rathbun. 



Bull. Buff. Soc. Nat. Sci., i, no. 4, p. 259, fig. 2, 1874. 



Rare in the Devonian shales of Erere, associated with Discina lo- 

 densis. (Morgan Ex., 1870; Geol. Comra., 1876.) 

 Discina lodensis Hall. 



Orbicula lodeiisis Vanuxem, Geol. Rept. Third Dist. N. Y., p. 168, 

 1842; Hall, Geol. Rept. Fourth Dist. N. Y., p. 223, 1843. Discina 

 lodensis Hall, Palaeont. N. Y., iv, p. 22, 1867; Rathbun, Bull. Buff. 

 Soc. Nat. Sci., I, no. 4, p. 257, 1874. Compare Discina media Hall, 

 Palaeont. N. Y., iv, p. 20, 186 7. 



This species is very abundant in the dark shales of the Devonian 

 of Erere, and the collections obtained from there, represent it in its 

 various stages of growth, from the very young to the adult shell. 

 (Morgan Exs., 1870 and '71; Geol. Comm., 1876.) 

 Productella msecuruensis, sp. nov. 



Shell small and slightly asymmetrical in shape; length and breadth 

 nearly equal, giving an irregularly subcircular outline to the shell, 

 which is somewhat flattened posteriorly; hinge line straight and 

 sliirhtly shorter than the width of the shell; cardinal extremities not 

 preserved in the single specimen obtained. 



Ventral valve very convex (but rather less so than is usually the 

 case in tiiis genus), quite strongly curved from side to side, and 

 strongly and nearly regularly curved from the beak to the front, 

 the point of greatest prominence of the valve being, however, 

 slightly posterior to the middle. Beak rather small, but strongly 

 arched and regularly rounded, and projecting some distance behind 

 the hinge line. The convexity of the umbo broadens with moderate 

 rapidity forward, leaving the portions of the valve bordering the 

 cardinal extremities slightly and irregularly flattened. The want of 

 symmetry in the ventral valve results from the beak and more promi- 

 nent line of curvature lying a little nearer the right margin than 

 the left. Dorsal valve unknown. 



