234 



MA.) OK IT. WALL, I.M.S., C.M.Z.S. 



I think that the Hydrophis godeffroyi (Peters), H. pachycercos (Fischer), and H. 

 poiyodontus (Jan) will probably prove to be specimens of this species and think the 

 Distira andamanica (Annandale) which I have examined, cannot be separated. 



Hydrophis godeffroyi was described by Peters in 1872 l from two specimens. Only 

 two other specimens are known, both of which are in the British Museum. The two 

 latter I have examined, and cannot find to differ in any way from specimens of orna 'a 

 in the British Museum. The only differences claimed for them by Mr. Boulenger 2 

 affect the rows of scales in the neck and body. Thus these are in ornata 35 to 42 in 

 the neck 40 to 50 in the body; in godeffroyi 28 to 33 in the neck, and 38 to 43 in 

 the body. I find, however, that in specimens of ornata in the British Museum the 

 anterior scales vary from 31 to 39, and in the godeffroyi from 30 to 33. Again the 

 scales in midbody in ornata vary from 36 to 45 ; in godeffroyi from 37 to 39. 

 Examined side by side with specimens of ornata they seem to agree in every respect. 



The description of Peters' type-specimens, one of which he figures, entirely agrees 

 with specimens of ornata. 



Fig. 48.— Hydrophis pachycercos. After Jan, Icon Gen.. 1872, 39, pi. vi. 



Hydrophi pachycercos was described and figured in 1856 by Fischer from a 

 single specimen. Jan figures another specimen, and a third so named is in the British 

 Museum. This last specimen, I have seen and consider, has every right to be called 

 ornata. The differences claimed bv Mr. Boulenger if one refers to his descriptions are — 



ornata. 



(1) Head moderate. 



(2) Rostral broader than deep. 



(3) Posterior chin shields not in contact. 



(4) Neck scales 35 to 42. 



(5) Body scales 40 to 50. 



pachycercos. 



(1) Head rather small. 



(2) Rostral as broad as deep. 



(3) Posterior chin shields in contact. 



(4) Neck scales 27 to 29. 



(5) Body scales 38 to 39. 



Of these differences the first is too indefinite , and the second too minute to discuss. 

 The third is again minute for the posterior chin shields only just touch in the British 

 Museum specimen labelled pachycercus. This is, moreover, a character constant in 

 but very few of the species. As regards neck and body scales, the differences claimed 

 vanish when the scales are counted as I count them at definite spots in the body 

 length, and then come within the range taken from my 36 specimens. Thus I make 

 the range for the anterior scales in ornata 30 to 41, the scales in midbody 33 to 46. 

 In pachycercus they are 29 anteriorly, and 39 in midbody. The British Museum 



1 Mon. Berl. Acad., p. 856, plate 1, fig. 3. 



2 Cat., 1896, vol.iii. pp. 290 and 291. 



