The printed pages are not numbered. The page numbers inserted here count 1 from the title page. Three odd-numbered (recto) pages are missing: 793, 815, and 837. In the original DjVu, this caused the following odd pages to be shifted forward, but this has been corrected.
Page headings can't be trusted. Both pages 660 and 667 have the heading EPH-EPI, but the pages are not duplicates. The latter contains headwords Eretia-Erinopterus and should have the heading ERE-ERI.