William H. Dougal (1822-1895) of Washington, D.C. produced this pre-press engraving proof of "Proctotretus Tenius, Proctotretus Femoratus, and Proctotretus Stantoni" from an original illustration by John H. Richard (1807- ca 1881). The image was published as Plate XL in Volume 2, following page 216 of Appendix F (Zoology Reptiles) by Charles Girard (1822-1895) in the report describing "The U.S. Naval Astronomical Expedition to the Southern Hemisphere during the Years 1849, 1850, 1851, and 1852" by James M. Gillis (1811-1865). The volume was printed in 1855 by A. O. P. Nicholson (1808-1876) of Washington, D.C.