22/ 



XX Second pair of chin-shields in contact or 

 separated by one scale. 

 O Scales all imbricate. 



a«. Ventrals 220 — 256; two postoculars. iS. //. niacfarlani p. 237. 

 /!'/'. Ventrals 281 — 385; two postoculars. 19. //. cyanocinchis ^.T.^"]. 

 cc. Ventrals 306; one postocular . . . 20. //. saravacensis p. 238. 

 00 Scales on posterior part of body jux- 

 taposed. 



a. 34 scales round body; ventrals 317. 21. //. belcheri p. 238. 



b. 38 or 39 scales round body ; 



ventrals 258 — 260 22. H. pachycerctis p. 239, 



2. Scales round body in 48 — 59 rows; ventrals 

 usually in pairs, except anteriorly, not larger 

 than the scales and pointed 23. //. stokcsi p. 239. 



I. Hydrophis frontalis Jan. 



Hydrophis frontalis^ J^ri^ Elenco 1863, p. iio. 

 Hydrophis frontalis^ Koulenger, Cat. Sn. Ill 1896, p. 276. 



Head very small; rostral more broad than deep; praefrontals 

 separated by the point of the frontal; latter more long than 

 broad, as long as its distance from the tip of the snout, shorter 

 than the parietals; one prae- and one postocular; two super- 

 posed anterior temporals; seven upper labials, third and fourth 

 entering the eye; chin-shields small, the posterior separated. 

 Body very slender anteriorly, scales rhomboidal, imbricate, 

 with a strong keel, in 42 — 45 rows (34 or 35 anteriorly); 

 ventrals 285 — 291. 



Yellowish-white, with greyish transverse bars, broadest on 

 the back; head blackish, a yellow band above and behind the 

 eye. Length of head and body 630 mm.; tail 65 mm. 



Type-specimen examined in the Leiden Museum. 



Habitat: Indian Ocean!; Java (Batavia, Pasuruan!). 



2. Hydrophis nigrocinctus Uaudin. 



Hydrophis nigrocinctus^ Daudin, Kept. VII 1803, p. 380. 



Plydrophis nigrocinctus^ Houlenger, Cat. Sn. Ill 1896, p. 277; Rept. Malay 

 Penin. 1912, p. 187. 



Head small; eye as long as its distance from the mouth. 

 Rostral more broad than deep; nasals shorter than the frontal, 

 about twice as long as the suture between the praefrontals, 

 which are separated from the labials; frontal more long than 



