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Show 22 DR. J. ANDERSON ON MAMxMALS, REPTILES, [Jan. 5, I have also given two drawings of its head (Plate I. figs. 6, 7). If these are compared with Guichenot's figure of V. mauritanica l, which Mr. Boulenger informs m e is a good representation of the above-mentioned specimen No. 4017, the differences between this variety and the typical form will be seen to be considerable. To summarize the features of this variety, the most striking is certainly the entire absence of any approach to keeling on the scales on the upper surface of the head from the parietal region forward to the rostral. As already stated, in all the hitherto recorded specimens of V. lebetina, the scales of the head over the foregoing area and over the upper surface of the head generally are keeled in various degrees of intensity, while at the same time they preserve to a great extent the general form and character of the scales on the body. In this variety, on the other hand, the head-scales, besides being perfectly smooth in the region specified, are somewhat unlike those of the body in that they are rounded at their margins and are very fiat. The entire absence of the canthus rostralis is another feature by which this variety is distinguished from the typical form, in which it is always defined although less marked in some individuals than in others. The rostral shield is higher than broad, but in an example of this species from the Lake of Galilee it is as high as broad, a modification which connects this variety with the other specimens mentioned in the foregoing table in which the rostral is decidedly broader than high. The supraoculars in the first six specimens enumerated in the table (p. 21) are not markedly differentiated from the ordinary head-scales as regards their size: occasionally one or more scales may be larger than the others, either on both sides of the head or on one only, but in none of them are two scales so developed as in this variety. On the other hand, the specimens from Persia and Afghanistan can be distinguished at once by the presence of a large supraocular occupying nearly the entire upper border of the eye. It will be observed that, in the labials and the scales between the eyes, the variations among these specimens are very insignificant. It is worthy of attention that the four specimens from the mainland of South-western Asia present a marked increase in the number of their ventrals as compared with the typical form from Algeria and Cyprus, and that the two groups are connected with each other by var. deserti from Eastern Tunisia. In V. lebetina, var. deserti, the colour is pale yellowish brown above, with very faint indications of the dorsal and lateral dark spots distinctive of Algerian and Cyprian examples of the typical form ; and the under surface is pale yellow, almost immaculate anteriorlv, the finely powdered aspect of the species being only feebly indicated posteriorly. The specimen from thej Lake of Galilee very much resembles the var. deserti in colour and general appearance, but it has keeled scales on the head and a canthus rostralis. I have selected the term deserti to designate this variety, because reptiles received from Duirat, the locality from which this Viper 1 Explor. Sc. Alg., Rept. pi. iii. |
