OCR Text |
Show 1891.] TADPOLES OF THE EUROPEAN BATRACHIANS. 619 but possessed of the usual grey, green-spotted coloration. Their small size alone distinguished them. It is clear that the abnormal colour of these tadpoles was not due to the surroundings at the time I observed them, as the water in which they lived underwent various changes during the five weeks I watched the pool; and specimens which I brought home and kept under the same conditions as normal larvae did not change colour. I am therefore able to confirm the conclusions arrived at by Heron Royer, from observations on larvae oi Alytes obstetricans (Bull. Soc. Zool. France, 1878, p. 65), that is, that the coloration is due to the conditions under which the larva develops on leaving the egg ; and that after that time, the pigment-cells becoming fixed and less sensitive, little or no alteration takes place until the end of the larval period. The largest tadpole of Pelodytes obtained by me in Brittaii}' measures 57 millim.: body 21, width of body 15 ; tail 36, depth of tail 14. A specimen from Nice, received from Dr. de Bedriaga, measures 65 millim. W e are indebted for the first account of this tadpole to Heron Royer (Bull. Soc. Zool. France, 1878, p. 131, pi. iii.), who pointed out that the larva described and figured by Lataste as of Pelodytes is that of Alytes obstetricans. He, however, erroneously represented the lines of muciferous crypts as decussating on the forehead; and this error was soon corrected by Lataste (Actes Soc. Linn. Bord. xxxiii. 1879, p. 309). Further notes were contributed by Heron Royer (Bull. Soc. Zool. France, 1879, p. 229, pi. xi.), and by the same author in conjunction with Van Bambeke (Arch, de Biol. ix. 1889, p. 277, pi. xx. figs. 5-12). The best description is that given by Bedriaga (Bull. Soc. Nat. Mosc. 1889, p. 539), who for the first time notices the pigmentary decussating lines. The habitat oi Pelodytes punctatus is restricted to France, where it occurs nearly everywhere with the exception of the central Plateau and the extreme North-east, being recorded as far north as the Pas-de-Calais (Giard, Bull. Sc. Fr. Belg. xxii. 1890, p. 87), Spain and Portugal, Liguria (Doria, Ann. Mus. Genova, xxiv. 1887, p. 388), and Piedmont (Peracca, Boll. Mus. Torin. i. 1886, no. 1). The tadpole usually lives in flooded quarries. I have found it in Brittany in company with tadpoles of Rana esculenta, R. tgilis, Bufo calamita, and Hyla arborea. A. Thomas (Ann. Sc. Nat. 4, i. 1854, p. 290) appears to have been the first to notice, at Nantes, that Pelodytes breeds not only in the spring, but also in the autumn ; and he assigned to this species two broods a year-the first from the end of February to the beginning of April, the second from the end of September to the beginning of October. Lataste (Actes Soc. Linn. Bord. xxix. C. R. 1874, p. cli) has witnessed its breeding, near Bordeaux, on the 22nd May, and (Actes Soc. Linu. Bord. xxxi. 1876, p. 11) near Paris on the 8th July. Thomas's statement regarding the autumnal breeding has been contested by Heron Royer (Bull. Soc. Zool. France, 1878, p. 131, and Bull. Soc. Et. Sc. Angers, 2, xv. 1885, p. 103), but is |