I'm having a small issue and hoping someone here can help (or point me to somewhere else appropriate to ask).

I am trying to attribute a photograph. It is a profile of a dead chimpanzee printed in roughly 1855 (based on dating the physical characteristics of the print). Someone prior to me credited the photo to "L. Rousseau". However, I cannot find any reference to an "L. Rousseau" in any scientific photography collection, the French Academy of Science, or any major museum collection. Anybody have a clue or new suggestions on where to look?