ARI-. 25 CHINESE AMPHIBIANS AND REPTILES STEJNEGER 71 



ing on the mid line with the corresponding pattern of the other side ; 

 on the body there are about 20 such black rings or half-rings ; on the 

 underside of the tail there are about 12, the larger ones being 5 to 6 

 pairs of subcaudaLs wide ; on- the posterior half of the underside the 

 light interstices are mottled with brownish gray. 



NATRIX PERCARINATA (Boulenger) 



1899. Tropidonotus percarinatus Boulenger, Froc. Zool. Soc. London, 

 1899, p. 163, pi. 17, fig. 2 (type locality, Kuatun, Fiikien ; type in Brit. 

 Mus. ; J. D. La Touche, collector). — Wall, Froc. Zool. Soc. London, 

 1903, p. 67 (Sikawei, Shanghai). — Werner, Abh. Bayer. Akad. Wiss., 

 II Kl., vol. 22, pt. 2, 1903, p. 354 (Ningpo mountains). 



Boulenger's species was based on a single male specimen from 

 Kuatun, Fukien. Since the original description appeared, specimens 

 from near Shanghai have been referred to it by Doctor Wall and by 

 Doctor Werner. 



Two specimens which I refer to N. jyercarinata were collected by 

 Mr. Graham at Si-gi-pin, Mount Omei, Szechwan. Compared with 

 A', aequifasciata they have a less elongate snout with relatively 

 shorter loreal and internasals; the supralabials are rather elongate, 

 however, especially the three posterior ones. In both specimens the 

 sixth supralabial is excluded from the eye by the subpostocular, but 

 in No. 66635 the fourth touches the eye on both sides. The eye is 

 rather large, the diameter exceeding the width of the frontal at 

 the middle in this specimen. The frontal is very large in both, 

 in No. 66635 with concave sides; parietals short, the suture between 

 them equaling or shorter than the distance of frontal from tip of 

 snout. The scale formula is as follows : 



No. 65455 sc. 19; v. 140; a. 2; subc. . . . ; 1. 9; oc. 1-4 ; t. 2+3. 

 No. 66635 sc. 19 ; v. 139 ; a. 2 ; subc. 52 ; 1.t% ; oc. 1% ; t. 2+3. 



The dorsal scales are very strongly keeled, but the two outer scales 

 are smooth and the third smooth or very weakly keeled. 



In coloration the Mount Omei specimens differ considerably from 

 N. aequifo^sciata. The upper side is nearly uniform gray with 

 faint indications of dusky cross bars more or less continuous with the 

 lateral markings which are more like those in the type of the species, 

 except that they are pale in the middle. The underside, hoAvever, 

 while lacking in the bold black cross blotches of the N. aequifasci- 

 ata, nevertheless approach the latter in having indication of a 

 similar pattern with the center of the cross bars faded out. In both 

 specimens the labials are dark like the rest of the head without the 

 blackish edffes to the sutures which are characteristic of N. annulans. 



