44 Mr. G. A. Bouleiigev — " Zur Ldsung 



which lie lays stress hopelessly break down when put to the 

 test of large series from move extensive areas than it is the 

 custom for faunists to deal with. An interesting example of 

 the danger of hasty generalizations of this kind has just come 

 under my notice. 



As I mentioned in describing the typical form of Lacerta 

 mitraUs *, one of the two specimens (topot3'pes) from near 

 Vienna, received from my ever-obliging friend Dr. Werner, 

 proved to be highly aberrant in several respects. 'J'he 

 parietal shields were abnormally divided by a transverse cleft. 

 On recently enquiring from Dr. Werner as to whether he had 

 other examples from the same locality (Voslau, near Baden, 

 Lower Austria), I was greatly surj)rised to hear that an 

 examination of his material had satisfied him that this 

 division, instead of being anomalous or accidental, is the rule 

 in Lower Austria. Among his specimens from Miklling, 

 Baden, Voslau, Reichenau, and Miesenbach, not one is without 

 at least an indication of it, whilst he cannot find such a thing 

 in any of his other specimens from various parts of Europe. 

 In order to further confirm this observation, Dr. Werner has 

 made excursions to Baden and Voslau, whence he sent me 

 six living examples, all showing a complete or incomplete 

 cleft across the parietal shields. Therefore this anomaly, 

 which very seldom occurs in other parts of the very exten- 

 sive habitat of the wall-lizard, although it is frequent in the 

 viviparous lizard f, appears to have become fixed in a small 

 district near Vienna. E. Martin \ mentions the case of 

 the inhabitants of a small secluded village in France, 

 nearly all of whom, at the end of the eighteenth century, 

 had an extra digit to both hands and feet; gradually, 

 however, as intercourse with neighbouring communities 

 became frequent, the deformity was wiped out. Some 

 years ago, when reporting his interesting discovery of 

 Lacerta praticola in a valley near Herkulesbad in Transyl- 

 vania §, Prof. V. Mehely pointed out the frequent presence of 

 an accessory shield between the interparietal and the occipital, 

 observed in 48 specimens out of 78; and as it so happened 

 that the unique specimen on which the species was estab- 

 lished by Eversmann offered the same anomaly, which occurs 



* Trans. Zool. Soc. xvii. 1905, p. 354, pi. xxv. fig. 4. 



t In which it may he trausmitted to the otTspring, as shown by a 

 female from the dunes near O.stend, which produced four young in 

 captivity (Aug. 4-7), all showing the same anomaly. 



X Hisloiredes Monstres, 1880. Quoted fromDelage,I/Il6redite,p. 194. 



§ Math. Naturw. Ber. Ungarn, xii. 1894, p. 255, and Zool. Anz. 1895, 

 p. 474. 



