E ;r R A. T A. 
Page 1, under Spirifer, add Plates xxvii and xlvi. 
Page 43, under Cyrtina, add Plate xxv ; change xxvii to xxviii. 
Page 47, under Stringothyris, add Plates xxv and xxxix. 
Page 51, under Spiriferina, add Plate xxix. 
Page 54, under Ambogcelia, add Plate xxix. 
Page 58, under Whitfieldblla, change Plate xlviii to xl. 
Page 61, under Hyattella, change Plate xlviii to xl. 
Page 63, under Hixdella, add Plate xlix. 
Page 65, under Mbristina, change Plate xlvii to xli. 
Page 70, under Merista, change Plate xlvi to xlii. 
Page 73, under Meristella, change Plates xliv and xlv to xliii and xliv. 
Page 8!?, under Camarospira, change Plate xlii to 1. 
Page 83, under Atuyris, add Plate Ixxxiii. 
Page 108, under Rhynchospira, add Plate xlix. 
Page 112, under Ptychosptra, add Plate Ixxxiii. 
Page 115, under Edmetria, add Plate Ixxxiii. 
Page 124, under Trematospira, add Plate Ixxxiii. 
Page 134, under Ccelospira, add Plates Hi and Ixxxii. 
Page 138, under Vitulixa, change Supplementary Plate to Plate Ixxxii. 
Page 141, under Anaraia, insert Plate Ixxxii. 
Page 142, under Noclbospira, add Plate Ixxxiv. 
Page 152, under Glassia, insert Plate Ixxxiii. 
Page 154, under Zygospira, change Plate Iv to liv, and add Plate Ixxxiii. 
Page 157, under Catazyga, change Plate Ivi to Iv. 
Page 161. under Atrypixa, add Plate Ixxxii. 
Page 163, under Atrypa, change Plate liv to Iv. 
Page 182, under Rhynchotrbma, add Plate Ixxxiii. 
Page 189, under Camarotcechia, add Plate Ivi. 
Page 202, under Pugnax, add Plate Ixii. 
Page 230, under IjYCopiioria, change Plate Ixiii to Ixii. 
Page 249, under Stricklaxdinia, add Plate Ixxxiii. 
Page 252, under Amphigenia, add Plate Ixxvi. 
Page 286, under Cryptonella, add Plates Ixxix and Ixxxi. 
Page 293, under Dielasma, add Plate Ixxx. 
