Continuing my developing sketches for a current client. After looking at my initial sketch of Tristan link I realized I'd made a mistake and decided to set about correct it which created some new problems. The different sections of membrane on a bat's wing perform different functions.link These sections are generally divided by the finger bones on the limb. The section of membrane closest to the body generates primarily just lift while the outer regions of the wing create most of the thrust for the bat. The location of finger bones play a critical part in these role, but in my initial sketch I had forgotten to include one of those fingers. Also the membrane on top of the arm acts as a leading edge on an aircraft.

Also I wanted come with a better hand structure for Tristan that looked at least a little bit more plausible. For the record, I am not a biologist, or a zoologist, I'm just a guy who likes to think about things and try to figure how to draw them. Also Tristan and Amelia are entire creatures of fantasy so not every joint of tendon might be in the right place.