515 



Orthis. 



characters belonging to Trematospira^ but with a more distinct 

 area than has been observed in any species of that genus; 

 while there is no sinus (groove) upon the ventral valve." Hall. 



Also, Pal. Ohio, Vol. 2, 1875, p. 76, 

 pi. 1, fig. 9 Vz, J, <3, back, profile, hinge 

 (showing very restricted area) ; d^ 

 M^ front views ; fig. 20, dorsal view of 

 Vr-^^ one of the original specimens on 

 which the species was founded. — Cincinnati^ Illh. 



Orthis emacerata, Hall, 13th Rt. 1860, p. 121; 15th An. 



mi 1 



m. 1862, pi. 2. fig. 1, 

 dorsal valve; 2, ven- 

 tral valve, interior ; 3, 

 \||?' same of a form ordi- 

 '^ narily referred to 

 Orthis testudinaria. — Cincinnati group {Hud. Riv.) lllh. — 

 Also Pal. Ohio, Vol. 1, 1873, p. 109, pi. 8, fig. 1 a, 5, c, dorsal, 

 profile and hind view of medium-sized normal specimen ; 1 c, 

 ventral view of a typical, more transverse specimen ; 2 a^ S, 

 dorsal and ventral larger specimen; 2 c^ d^ interiors of ventral 

 and dorsal valves ; 2 ^, profile oi ^ a ; 2 /*, hinge of same ; 2 g^ 

 much magniUed surface minute lines of growth crossing fur- 

 rows between striae. 

 Orthis emacerata, Var. multisecta, James, Pal. Ohio, p. 



112, pi. 8, fig. 3 a, 

 5, ventral and 

 hinge views; 3 c, 

 interior of dorsal 



3cL 



S~"'^ 



:a 



valve, showing muscular scars, hinge and brachial processes 5 

 4 d. magnified surface strias, showing them crossed by another 

 excessively fine series, in furrows. Cincinnati group ^ Tllh. 



