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PROCEEDINGS OF THE NATIONAL MUSEUM, 



essentially like the two other specimens, 

 having the lo^A'e^ anterior temporal 

 widely separated from the labial edge, 

 but the parietal is separated from the 

 lower postorbital. It is a female. No. 

 67737 and its scale formula is as follows : 

 sc. 17; V. 178; a. 2; subc. 124; oc. 1-2; 

 t. 2-1-2 ; supral. 9. 



Genus NATRIX Laurenti 



Three names of water snakes {Natrix) 

 occurring in southeastern China cluster 

 around the identical scale formula : 19 

 sc; 132-164 v.; 2 a.s 51-77 subc; 1-3 or 

 4 oc; 2-[-3 temp., namely, N. annularis, 

 A', hahereri, and N. percayinata. This 

 formula overlaps that of a fourth species 

 of wide distribution but extending its 

 range into the same region, namely N. 

 piscator, the formula of Avhich is : 19 sc. ; 

 125-150 V. ; 2 a. ; 70-90 subc ; 1-3 (4) oc. ; 

 2-1-2 or 3 temp. The character relied 

 upon for distinguishing the latter has 

 been that two or three outer scale rows 

 were supposed to be smooth and only one 

 in the other three forms. We now know 

 that this distinction does not hold. 

 Speaking of the character assigned to 

 Nat/ix asperrima, viz, one unkeeled row 

 of scales as against two or three in yV. 

 piscator, Doctor Wall states that he ex- 

 amined many hundreds of Indian pis- 

 cat o?' and found that the number of rows 

 not keeled is variable. He also examined 

 several of the Ceylon form asperrima 

 most critically, besides the Indian pis- 

 cator, and could not discover any con- 

 stant character whereby the tw^o can be 

 separated. In addition it now turns out 

 that both the types of N. annularis and 

 N. habereri have three smooth, or nearly 

 smooth, outer scale rows, and that in 

 several other specimens of this form the 

 second scale row is more or less smooth. 

 It will be noticed, however, that in the 



