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 specim"en, 9 mm. ; width along hinge-line, 10 mm. 



Upper Devonian. Rockford, Iowa. 



ERRA.T^. 



Pag-e 57, line 12 from bottom ; for " Plate I " read " Plate II." 



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



Page S3, line 5; for "Leotobolus" read "Lbptobolus." 



Page 99, line 23 ; for "and" lead "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 ; Shakpe's ppecimens came from Cincinnati, Ohio, or vicinity, and were 

 probably examples of the form now known as T. millipunctata. Hall, as Emmons' T. tenni7Miis has not been 

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

 retahi the New York form as such. 



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



Page 185, line IS; for " Strophodonta " read "Stropheodonta." 



Page 194, second paragi-aph. The deltidium of Orthis? Laurentina is minutely pei-forate. 



Page 288, line 15; dele "are." 



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



Page 308, line 5; for "C. undwlatws" read " C. undulata ;" for "C. Navascoticus " read C. No^m- 

 .wotUa." Corrected in part of the edition. 



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



Explanation of Plate I, line 25; insert "(?)" after "LirigiUa Vanhomii, Miller"; line 28, dde ; read 

 " Trenton horizon. Frankfort, Kentucky." 



Expiation of Phite IVb, continued, line 8; for •' OrbiciUoidea piUchm" i-ead " Orbiculoidea Herzeri." 



Explanation of Plate IVf, line 33; for " Orbiculoidea piUchm" lead " Orbiculoidea Herzeri." 



