354 PALEONTOLOGY OF NEW YORK. 



tered spines, of which there is a well-defined row of six or seven on the car- 

 dinal margin. There are faint, irregularly concentric wrinkles among the 

 spine-bases. Apex of the brachial valve convex but the valve rapidly be- 

 comes concave, being of somewhat less curvature than the opposite valve. 

 Surface with conspicuous, irregular, concentric corrugations, and a few short 

 spines over the pallial region. 



Length of the original specimen, 9 mm. ; width along hinge-line, 10 mm. 



Upper Devonian. Rockford, Iowa. 



EKRA.T^. 



Page 57, line 1'2 from bottom ; for " Plate I " read " Plate II." 



Page 75, line 6; for "position" read "portion." 



Page S3, line 5; for "Lkotobolhs" read "LEPTOBOLns." 



Page 99, line 23; for "and" read "are." 



Page 99, line 24; insert "which" after "25-29)." 



Page 108, under fig. 60 ; for "pedicle" read "brachial ; " for "brachial" read " pedicle." 



Page 139, line S from bottom ; Sharpe's specimens came fi-om Cincinnati, Ohio, or vicinity, and were 

 probably examples of the form now known as T. mUlipU7ictata, Hall, as Emmons' T. termhmlis has not been 

 found in that locality. Sharps, however, mentioned Emmons' species as the type, and it may be best to 

 retain the New York form as such. 



Page 173, line 4 ; for " Lingiila llngidata " read " Lingula I'mguata." 



Page 185, line IS ; for " Stkophodonta " read "Stkopheodonta." 



Page 194, second paragraph. The deltidium of Orthis? Laurentina is minutely perforate. 



Page 288, line 15; dele "are." 



Page 303, line 2 ; for " XVa" read "XVb." 



Page 308, line 5 ; for "0. mididaUis" read " C. undulata ; " for " C. Novascoticus " read C Nova- 

 scotica." Corrected in pai-t of the edition. 



Page 32S, line 1 ; for " 1847 " read " 1867." 



Explanation of Plate I, line 25; insert "(?)" after "Lingula Vanhornii, Miller"; line 28, dele; read 

 " Trenton horizon. Frankfort, Kentucky." 



Expiation of Plate IVe, continued, line 8; for " Orbicido'idea pulcJira" read " Orbiculoidea Herzeri." 



Explanation of Plate IVp, line 33; for " Orbiculoidea pulchra" read " Orbiculoidea Berzeri." 



