356 OPHIDIA. 



number of longitudinal series on the body varies much, from nineteen to twenty-five, in 

 different individuals, mthout affording a character for specific distinction ; it is more constant 

 on the front part of the trunk. The ventral shields are broad, and sometimes show a lateral 

 keel. Anal bifid. The tail is longer and thicker in males than in females, and covered with 

 high, short, shield-like scales, the two lower series of which may be considered as subcaudals. 



The poison-fang is short, and not followed by a series of other simple teeth as 'va.Hydrophis. 

 A very small single tooth is implanted at some distance behind the poison-fang, and is fre- 

 quently lost. 



These snakes have quite the physiognomy of an Elaps, and the cleft of the mouth is not 

 turned upwai'ds behind as in other sea-snakes ; the eye is rather small. Neither the tail 

 nor the hind part of the body is prehensile ; and although we have not received positive 

 information concerning their habits, it becomes evident from their whole organization that 

 they must differ considerably from the other types of the family in this respect. 



Platurus scutatus. 



Coluber laticaudatus, L. Mus. Ad. Fried. 1754, tab. 16. fig. 1. 

 Laticauda scutata, Laur. Syn. Rept. p. 109. Cantor, Mai. Rept. p. 125. 

 Hydrus colubrinus, Schneid. Hist. Aniph. p. 238. 

 Platunis fasciatus, Latr. Rept. iv. p. 185. 



Hydrophis colubrinus, Schley. Phys. Serp. ii. p. 514. taf. 18. figs. 18-22; Faun. Japan. Rept. 

 p. 92. tab. 10. 



Generally an azygos shield between the posterior frontals ; scales of the front part of the 

 trunk in twenty-one or twenty-three longitudinal series; ventral shields from 213 to 241. 

 Body surrounded by from twenty-five to fifty black rings. Crown of the head black ; the 

 first and second black mark of the head and neck are joined below by a black longitudinal 

 band, commencing from the chin ; snout and side of the head yellow, with a black band 

 running through the eye. 



After having examined nearly fifty examples of this species, I have come to the conclusion 

 that the number and width of the black cross bands do not constitute specific characters 

 in these snakes. The length of the tail also varies with the sex. It is a common species, 

 extending from the Bay of Bengal to the Chinese seas and to the coasts of New Zealand. 

 The largest example I have seen is exactly 5 feet long. 



Platurus fischeri. (Plate XXV. fig. A.) 



Platurus fischeri, Jan, Iconogr. desci'ipt. in Rev. et Mag. Zool. 1859. 



No azygos shield between the posterior frontals ; scales of the front part of the trunk in 

 nineteen longitudinal series; ventral shields 232-241. Trunk surrounded by from thirty- 

 three to thirty-six black rings, which are broader than the interspaces. A black band crosses 

 the occiput and extends forward over the vertical plate and over the lower jaw, but, gene- 



