V\ 



CORRIGENDA. 



Plate 1, tig. 8. Some of the short spines at the summit of the proboscis are erroneously merged 

 into the branches of the arras, making the latter appear as if continuations from the spines. 



Plate 4. The references of tigs. 10 and 11 should be reversed. 



Plate 12, figs. 9, 10, 11 & 12. Orthis quadrans, referred to in text as O. subcarinutu. A study of 

 the interior structure of the valves has shown these forms to be quite distinct from O. subcarinata, 

 and a well-marked species. 



Pt.ATE 68, p. 341. Bucania profunda (^B. profunda, n. s., by mistake) should be cited Eaomphalus 

 profundus, Vanuxem, Geol. Report Third District New-York, p. 117, f. 2. 



Plate 72 a. Erroneously referred to in the text, pages 347 and 348, as Pl. 62 a. The correction on 

 explanations of plates does not correct the reference. 



Plate 73, tig. 24 o, is an enlargement of a portion of the eye of P. hudsonicus. 



,% Plates 79 a and 79 b, containing figures of Leperditia and Beyrichia, are omitted from this 

 volume, but will be given in a future one. 



Plate 95 a. The reference f, after Strophodonta magnifica, should be after Orthis aimberlandia.'\ 

 t This species may be compared with Orthis hipparionyx. 



Plate 106. Explanations of figures omitted : 



Fig. 3. Rhynchonella muHistriata, p. 440. 

 Fig. 4. Rhynchonella principalis, p. 443. 



Plate 92, and page 406, change the name Discina grandis to Discina ampla, n.s.; the former 

 name being preoccupied. 



»•» In the text of the Introduction, page 8, in the righthand column of names of rocks, the Galena 

 limestone Ls by mistake placed below the Trenton limestone, when it should be placed above. 



