I’m in love with  classic scientific illutrations. These illustrations about general herpetology are from ‘Erpetologie Generale, ou, Histoire Naturelle Complete des Reptiles’ by AMC Dumeril & G Bibron, 1854. 

The multi-volume series, ‘Erpétologie Générale, ou, Histoire Naturelle Complète des Reptiles’, was released over a twenty year period beginning in 1834. Based on information from Bibliodyssey, the final volume is an atlas with more than one hundred steel engravings that were (I presume) hand-coloured.