Ennion, an English country M.D., produced an amazing collection of field sketches. Cahalane, Victor H. Mammals of North America. Hundreds of superb pen and ink and scratchboard drawings by Francis Lee Jaques. Cuvier, George and Laurrillard. Full of stunning anatomical drawings of a whole range of creatures.
Text is French, drawings speak for themselves.
Widely reprinted and easier to track down than you might think. DeJoode, Ton and Anthonie Stolk. The Backyard Bestiary. Alfred A. Knopf, Inc. 1982. Full of very nice pencil and watercolour drawings by Kees de Keifte.