Until now the Elapid genus Denisonia had not been recorded from New Guinea, and this is remarkable in so far as the genus is known from Australia (and Tasmania) to the south, and from the Solomon Islands to the northeast of New Guinea. It is therefore not very surprising that now evidence has been procured of the presence of the genus in New Guinea. A single specimen of a species that we believe to be new to science was collected at Merauke in southern West New Guinea by Mr. A. J. M. Monsanto in 1959. The genus Denisonia is here accepted in its old sense, such as it was used by Boulenger (1896, p. 332), and by the majority of subsequent authors. Recently, Worrell (1961a; 1961b, pp. 24-26; 1963) has made attempts to divide Denisonia into eight genera, but as yet the new genera diagnosed by him do not seem to be well founded. In his key to seven of the genera distinguished by him at that time, Worrell (1961b, p. 25) uses inter alia the character "preocular and prefrontal scales in contact" as opposed to "preocular and prefrontal scales not in contact". However, in all species concerned the preocular is in contact with the prefrontal. Probably Worrell meant to indicate that in one of the genera described by him (Unechis) the prefrontal borders the preocular not only above, but also anteriorly, thus reaching the labials, and separating the nasal from the preocular; in other genera described by Worrell (1961b: Cryptophis, Drysdalia, Parasuta, and also in Suta and Denisonia Krefft) the preocular is in contact with the nasal, separating the prefrontal from the labials. However, it may be pointed out that this character is subject to individual variations. Thus, Boulenger (1896, p. 345) already stated that in Denisonia pallidiceps (Günther), the type