Many years ago, I happened across an account by a biologist --- citation alas long-forgotten --- who as a student had dutifully absorbed the well-known fact, immortalised in all the best textbooks, that the pancreas secretes amylase (or some other enzyme) in every mammalian species --- with the sole exception of the rhinoceros. As time went by, he prospered in his profession, and reached at last that pinnacle at which he could command the acquisition of a genuine rhinoceros pancreas (by then unattached, presumably, to its previous owner) in order to satisfy a persistant though entirely natural curiosity concerning whatever physiological peculiarity might be responsible for such an idiosyncrasy. And whaddya know? It did secrete amylase (or whatever it was) after all! [I don't suppose anyone can remind me of my long-forgotten source for this history?] Since then, I have encountered numerous rhinoceros' pancreases (or whatever the plural is). Here's the latest. In books on (fairly) elementary geometry will be commonly be found a construction credited to Klein, in which the usual hyperbolic, elliptic, Euclidean, etc. flavours are specialised from (say 3-space) projective geometry by choosing an "absolute" quadric K --- say c w^2 + x^2 + y^2 + z^2 = 0 with c constant, [x/w, y/w, z/w] Cartesian coordinates of a general finite point. The desired symmetry subgroup is selected by the constraint that K remains invariant. A standard account then proceeds along the lines of an associated polarity, quadric degenerate when Euclidean, winding up with "when c < 0, hyperbolic; c = 0, Euclidean; c > 0, elliptic". 'Ang abaht --- when c = 0, K represents a single (real) point at the origin --- that's not invariant under translation ??!! It seems that what the original author must have had in mind was rather the polarity, for which the quadric was simply a shorthand. In the Euclidean case the polarity turns out to be [w,x,y,z] -> [0,x,y,z]; that is, actually c = oo --- obviously enough, since the other geometries approach flatness as their radius increases. A recent transcription of this momentary lapse of XIX-th century concentration --- from Klein himself, perhaps? --- turns up in Judith N. Cederberg "A course in modern geometries" (2001), in section 4.12 on page 299 --- there in 2-space rather than 3-space. This particular pachyderm will doubtless still be trotting around, in 2-space and 3-space, for another 100 years. A little depressing, innit? Fred Lunnon