May, 1917] Silurian Fossils from Ohio 247 



That Leplcena lovcui, Vcrneuil (184cS, Leptaena a crochet 

 perfore, Bull. Soc. Geol. France, p. 31 of reprint, PI. 4, Fig. 5), 

 from the Silurian of Gotland, is not a true Strophomena is shown 

 by the general concavity of the brachial valve and convexity of 

 the pedicel valve. The species probably is more stropheodon- 

 toid than strophomenoid although it presents some anomalous 

 characteristics, and probably should be relegated to a distinct 

 genus. Its surface ornamentation is somewhat similar to that 

 of Leptccua stephani, Barrande, but the transverse markings are 

 described as zig-zag in direction. 



Orthis loveni, Lindstrom (Gotlands Brachiopoder, Oversigt 

 af K. Vet. Akad. Forhandl., 17, 1861, P. 369, PI. 13, Fig. 12), 

 from the Silurian of Gotland, is a species of Rhipidomella closely 

 resembling Rhipidomella hybrida and does not present the 

 transverse zig-zag ornamentation here in question (Hall and 

 Clarke, 1894, Pal. New York, 8, Pt. 2, P. 359). 



Strophomena Julia, Billings (Palaeozoic Fossils, Canada, 

 1865, P. 127, Fig. 105, a, b) from the Jupiter River division of 

 the Silurian on Anticosti Island, also appears to be a stropheo- 

 dontoid species, judging from the very narrow deltidium and 

 the interior of the brachial valve. The transverse undulations 

 cross each other more or less in zig-zag manner. 



Similar forms of shells, probably stropheodontoid in char- 

 acter, were described by Kindle (Mus. Bull. 21, Canada Geol. 

 Surv., 1915, P. 13, 14, PI. 1), from the Silurian dolomite of the 

 lower Saskatchewan River valley in Manitoba, Canada, under 

 the terms Leptceiia sinuosus (Figs. 1-4) and LeptcEim parvula 

 (Figs. 5-9). Transverse wrinkles cross each other more or less 

 in zig-zag manner. 



Orthis (?) glypta, Hall and Clarke (1894, Pal. New York, 8, 

 Pt. 2, P. 359, PI. 84, Figs. 8, 9), from the Racine dolomite near 

 Milwaukee, Wisconsin, with diagonally intersecting wrinkles, 

 also may be a stropheodontoid, rather than an orthoid shell. 



Of the forms here cited, Leptccua stephani, Barrande, has 

 little in common with the remaining species. The remainder 

 may be congeneric. Too little is known at present, however, 

 regarding their internal markings to verify this suggestion. 

 Although apparently stropheodontoid in character, they may 

 form a distinct genus, not because they have a similar surface 

 ornamentation, but because these Silurian representatives of 

 the stropheodontoid group may present characteristics not 

 shared with the typical late Devonian species of Stropheodonta. 



