SUPPLEMENTARY NOTES AND OBSERVATIONS. 393 



Platyceras campanulatum, W. and M., pa. 99, seems to be only one of 

 the phases assumed by Platyostoma niagarensis in its wide geographical 

 distribution. 



Orthoceras nodocostum (M'Chesney), W. and M., pa. 101. Prof. WiN- 

 CHELL says, " No annular striae can be seen on our specimens. The longi- 

 " tudinal ridges are barely discernible on the shell, and leave no trace upon 

 *' the cast." The figure of Mr. M'Chesney represents annular stria) upon 

 his specimens, and I have never seen the shell without these markings . 

 and the casts, or partial casts, usually show the longitudinal ridges more 

 distinctly than the shell. 



I have received from Prof. "Winchell a gutta-percha cast, under the 

 name O. nodocostum ; and I have likewise had an apportunity of examin- 

 ing, in Prof. Marcy's collection, the matrix from which this cast was 

 taken. This matrix, although obscured by the crystalline matter which has 

 taken the place of the shell, nevertheless preserves the marks of annular 

 striae, quite as distinctly as it does the longitudinal ridges or nodes. It is 

 unnecessary to multiply remarks upon this fossil. 



Gomyhoceras marcycB, W. and M., pa. 101, is G. scrimum. Hall. 



Lituites hercules, W. and M., pa. 102, pi. iii, f. 9. The shell is not a 

 LiTUlTEs, but a Cyrtoceras of large size, presenting some peculiarities, 

 and described by me as C. amplicorne. The original specimen, communica- 

 ted by Prof. Maroy, has enabled me to make this correction of the spe- 

 cific name. 



Gyroceras hannisteri, W. and M., pa. 102. The gutta-percha cast from 

 Prof. Winchell, under this name, is a species of Trochoceras = 

 Trochoceras hannisteri. 



Lichas pugnax, W. and M., pa. 103, pi. iii, f. 10, I have already pointed 

 out the difi'erences between this species and L. h'eviceps ? The representa- 

 tion of the pygidium by Prof. Winchell is very unfortunate. The third 

 or posterior annulation of the figure is the anterior one of the axis. The 

 two anterior ones of the figure have no connexion whatever with the pygi- 

 dium, and do not exist in the specimen ; nor is there anything resembling 

 them. The anterior margins of the lateral lobes, as well as the anterior 

 border of the single annulation, clearly show the limits of the pygidium in 

 that direction. The left lateral lobe should be carried a little higher at the 

 axial furrow, and the right side be continued in a similar manner, leaving 

 off the two anterior rings of the axis. This condition is clearly shown in 

 the original specimen. 



Bronteus occasus, W. and M., pa. 104, pi. iii, f. 12. The specimens 

 communicated by Profs. Winchell and Marcy under this name are 

 identical with Bronteus acamas, being only smaller specimens. The figure 

 cited above conveys a very imperfect idea of the fossil. 



[Assem. No. 239.] 50 



