Hi Jools,
just did some research into this. And it did not become any clearer..
First,
provided there is only one series of books/journals titled
Proceedings of the Zoological Society of London, then the issues/pdfs are in principle available from Wiley:
http://www3.interscience.wiley.com/jour ... 0646/issue (this link should go to the 1895 issue containing p. 527).
According to our catalogue, we are supposed to have this in the University library (no online access).
However: if you quickly check the table of contents, Boulenger is not mentioned as author in that issue at all.
Ferraris in his checklist states that the first description is in:
Boulenger, G.A. (1895b) [Abstract of a report on a large collection of fishes formed by Dr. C. Ternetz in Matto Grosso and Paraguay, with descriptions of new species]. Proceedings of the Zoological Society of London, 1895, 523–529.
So it would be possible that this abstract is given in one of the reports of that issue.
That is a thing I could (provided no one has this book/paper/pdf at hand) check in our Library, but that would take a few days to get organized.
Regarding a picture, Ferraris states that one of the syntypes is displayed in:
Boulenger, G.A. (1896c) On a collection of fishes from the Rio Paraguay. Transactions of the Zoological Society of London, 24, 25–39, pls.1–6.
This one, we are also supposed to have in the Universities Library, and it is even available as PDF (though no access on my side):
http://www3.interscience.wiley.com/jour ... 7301/issue
Note, however, that it is from 1897 and not 1896 as stated in Ferraris.
So bottom line would be, that the reports by Boulenger should be available at our Universities Library. This is no guarantee, as I learned that occasionally, some issues are missing (usually those I would like to see).
But if no one else has easy access to those books, I could order them and see if they are really available. If so, I could copy them (nothing else allowed with these old books, usually) and scan the image.
That is one tough nut!
Cheers, Sandor