In an attempt to find an article on horse anatomy and conformation that I had read a few months ago, I happened to stumble across these illustrations by Benjamin Waterhouse Hawkins by accident. They come from a book entitled A Comparative view of the Human and Animal Frame which was published in 1860 and which has now been scanned into a web collection by the University of Wisconsin. I was most interested in the two images involving the horse, shown below, but there are many other interesting illustrations including some comparing humans to elephants, lions, antelope and bears within the collection.
Of course, browsing through that collection led me to another wonderful find as the University also has a great collection of veterinary illustrations by Hermann Dittrich, a German medical/veterinary illustrator from the early 1900s who I've admired for quite awhile (after all, veterinary illustration is one of my interests). A few of my favorites are shown below but it is definitely worth browsing through the entire collection, especially for anyone interested in veterinary illustration. In addition to the horse, the collection includes illustrations of cows, dogs, lions and deer in some of the most detailed and beautiful veterinary illustrations I've seen (click on the images to view larger).
Source: University of Wisconsin Digital Collections