Colour-Variation in Lizards.—Corsican Herpetology

Abstract

IN a communication sent to you by my friend Mr. Wallace, under the title, “Remarkable Local Colour-variation in Lizards,” published in NATURE, vol. xix. p. 4, mention is made of the well-known case of Lacerta (Podarcis) muralis, var. faraglionensis, only found on the Outer Faraglione of Capri, but there are many similar cases to my knowledge, and I add a note of them, for the fact, although unexplained, is one of great interest. During the last two years, while engaged in forming a complete series of the Italian vertebrate animals, I have visited and explored most of the Mediterranean islands included in the Italian sub-region, and I have invariably found that our common lizard (Podarcis muralis) constantly presents dark varieties on islets adjoining small islands: this is the case on the Scuola, near Pianosa, on the Scoglio di Mezzogiorno, off Palmarola (Ponza), on S. Stefano, off Ventotene, on the Toro, off Vacca (Sardinia), on Lisca nera, Lisca bianca, and Bottaro, off Panaria (Lipari), on Filfla, off Malta, and on Linosa, near Lampedusa. The extreme cases are those of the Faraglione off Capri and Filfla, where a nearly intense black is obtained; next comes Toro, and next Linosa; only the latter case might be explained by the “struggle for existence” theory, for the lava rocks of Linosa are black; but such is certainly not the case with the other islets, and, pace Dr. Eimer, the Faraglione is gray, while Filfla—on which I spent a pleasant day in October last—is painfully white in the glaring Maltese sun, so that its black lizards are most conspicuous. I may add that few creatures I know vary more in colour than Podarcis muralis, even in the same locality; two most distinct varieties occur promiscuously on the small flat islet Formica di Grosseto.