3a. Head appears elongate, very cone shaped, snout distinctly tapering, dorsal part flattened, ratio of head length to postocular height 0.28 - 0.29; head to body ratio 0.32 - 0.37; body frequently with black blotches forming 'port-hole' -like effect, blotches occasionally merging to form very irregular longitudinal stripe (Malaysia, Singapore, Java, Sumatra, Borneo).
b. Head not elongate, snout rounded, dorsal part slightly convex, not flattened, ratio of head length to postocular height 0.36; head to body ratio 0.30; body frequently with relatively regular longitudinal stripe, occasionally 'port-hole'-like effect not usually obvious (Sumatra, Borneo).
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