HERPETOLOGY OF JAPAN. 



293 



Dimensions. 



mm. 



Total length 517 



Snout to vent 415 



Vent to tip of tail 102 



Boiilenger records a specimen of this species measuring 820 mm. in 

 total length. 



The young (U.S.N.M. No. 34049; Formosa), total length 212 mm., 

 tail 42 mm., is quite like the adult, only darker with more sharply 

 defined pattern on sides and abdomen; four outer scale rows on each 

 side as light as underside. 



Variation. — The number of supralabials varies between 8 and 9, 

 and the one entering the eye is the fourth or the fifth accordingly. 

 Boulenger states that two supralabials rarely enter the eye. There is 

 occasionally only a single anterior temporal. Ventrals vary between 

 145 and 163 (in twelve specimens), subcaudals between 53 and 69 

 pairs (in 8 specimens). 



Habitat. — -Restricted apparently to Formosa and southeastern 

 China, where it has been found as far north as Ningpo and in the 

 Yangtse Valley as far west as Kiukiang. 



In Formosa it has been collected by Swinhoe, whose specimens are 

 in British Museum. The United States National Museum also has 

 two specimens from northern Formosa obtained recently from Mr. A. 

 Owston. 



List of specimens of Natriv annularis. 



"Description, p. 291, figs. 253-255. 



SBoulenger, Cat. I, p. 233. 



NATRIX SWINHONIS o (Guenther). 



1868. Tropiaonotus swinhonis Guenther, Ann. Mag. Nat. Hist. (4), I, 1868, p. 420, 

 pi. XIX, fig. Fb (type-looality, Formosa; type in Brit. Mus.; R. Swinhoe, 

 collector).— BouLENGEK, Cat. Snakes Brit. Mus.. I, (1893), p. 218 (For- 

 mosa) . 



1888. Tropidonotus swinhoei Boettger, Offenbach. Ver. Naturk. 26-28 Ber., 

 p. 137 (emendation). 



a For Robert Swinhoe, who collected the type; see p. 184. 

 bSee this work, fig. 256. 



