This is not a hand-colored engraving, it is an original, gorgeously executed ink and watercolor drawing—one of several I purchased from a seller in Germany, and which appear likely all done by the same person, c. 1840s I believe. Whether made in advance of, or after, an engraving for a zoological volume I am not certain (though I'd guess the former)--whatever the case, quite spectacular, and with the execution amplifying a sense of wonder at creatures that already seem quite wonderous! I've tried doing some translation of the cursive inked names under each to understand exactly what species are being represented-- here I believe a Red Ruffed Lemur top left and Ring-tailed one top right, a Golden-headed Lion Tamarin at lower left, and what I believe is a Bamboo Lemur lower right. Seems there has been some reclassifying/renaming since this was done, which makes the rendering feel all the more of another world. Marvelous. 

10 5/8" x 8 5/8" and in very good condition. The last photo was shot directly over a lamp, to give a sense of the paper, which appears to me to be wove--relatively thin but quite strong and durable.