432 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



equal jaws. Such a view does not, however, seem justified in view 

 of Hamilton's two positive statements in the description of the spe- 

 cies: (1) That the lower jaw is three times as long as, and (2) three 

 times longer than, the upper. 



Mohr (1926a) gave Zenarchopterus ainblyurus full specific rank and 

 regarded the fish that Day described and figured as ectuntio as the 

 female of Z. amhlyurus^ although Day referred to the thickening of 

 anal rays in the male. In Mohr's description of airiblyurus and in the 

 synoptical table of the characters of the recognized species, this form 

 is shown to have the length of the upper jaw more or less than twice 

 its width, the length of the lower jaw beyond the tip of the upper jaw 

 2 to 2.75 times the length of the latter, dorsal fin with second to fifth 

 rays elongated in the male, and anal fin with the fifth and sixth rays 

 enlarged and thickened in the male. The description and figure of 

 Z. amblyurus given by Bleeker (301) indicate a lower jaw which 

 projects 0.5 times the length of the upper jaw beyond the point of the 

 latter. If the ratio of the length of the upper jaw to that of the lower 

 jaw is of significance in this genus, as Mohr's studies would seem to 

 indicate, two species or varieties may have been included under the 

 name amblywims. 



Throughout Thailand the fish is known as pla katung heo. 



ZENARCHOPTERUS GILLI, new name 



Hemirhamphus 'brevirostris GtJNTHEB, 1866, vol. 6, p. 274 (East Indian 

 Archipelago). 



Uemiramphus dispar \on Martens, 1876, p. 401 (Bangkok). 



Hemirhamphus dispar Sauvage, 18S3b, p. 151 (Menam Cliao Phya). 



Zenarchopterus dispar Weber and de Beaufort, 1922, vol. 4, p. 169, fig. 58 (Siam). 



Zenarchopterus brevirostris Mohb, 1926a, p. 250, fig. 15 (East Indies, Singapore, 

 Siam, Caroline Islands, Fiji Islands, Guam, Andamans, Seychelles, Mada- 

 gascar, Mozambique). 



This species in Thailand is known from the lower Menam Chao 

 Phya. 



The contention of Mohr (1926a) that the Z. dispar of Weber and 

 de Beaufort, and of various other authors, is not the species originally 

 called dispar {Hemiramphus dispar Cuvier and Valenciennes) seems 

 justified. The sixth and seventh anal rays in dispar are greatly en- 

 larged, thickened, and elongated, and one or both of them may extend 

 well on the caudal fin. In brevirostris only the sixth anal ray is notice- 

 ably enlarged and lengthened, with a large number of subsidiary rays 

 developed on its posterior side, and it may reach as far as the posterior 

 end of the caudal fin ; the seventh ray, however, shows a tendency to 

 become longer and thicker than the remaining rays. In Weber and 

 de Beaufort's account of the form called Z. dispar, which Mohr 

 synonymizes with Z. brevirostris, it is stated that "in males the 6th and 

 7th ray are enormously enlarged and thickened," indicating that true 



