ERRATA. 



Page i6g, 22nd line, read Mosasauridte Gervais, 1853. 



Page 187, insert after "Length 5 ram." the following paragraph: 

 Two specimens, Magdalena Mts., Socorro Co., N. M. (F. H. Snow, 

 Aug.) 



Page 187, 8th line, read styliform instead of stillifortn. 



