seum in 1969-70, 1 visited the Sydney fish market 

 almost every week to obtain fishes. Origin of 

 specimens from throughout New South Wales 

 was determined by identifying the fishery coop- 

 erative which offered each box of fish for auction. 



On 8 April 1970, I selected, more or less at 

 random, four sea garfishes from several boxes 

 of large specimens from Eden, New South Wales. 

 (These specimens, all females, have been cata- 

 logued into the U.S. National Museum collec- 

 tions: USNM 207518-292 mm standard length; 

 207519-269 mm; 207520-280 mm; and 207521- 

 264 mm). The smallest of the four specimens 

 (USNM 207521) was separated from the other 

 three on the basis of its low gill-raker counts 

 (29 on the first arch, 22 on the second). This 

 count is characteristic of the Victorian popula- 

 tion of Hy. melanochir (Table 1). Two of the 

 other three specimens (USNM 207518-9) had 

 gill-raker counts typical for Hy. australis. The 

 fourth specimen (USNM 207521) had gill-raker 

 counts intermediate between Hy. melanochir and 

 Hy. a^istralis. 



The small specimen of Hy. melanochir had 17 

 dorsal and 19 anal rays in agreement with the 

 modes for the Victorian population (Table 1). 

 The pair of Hy. australis had 16 dorsal and 18 

 anal rays in agreement with the modes for that 

 species. The fourth specimen, like the Hy. mel- 

 anochir, had counts of 17 dorsal and 19 anal rays. 



Intermediacy in gill-raker count suggested 

 that the fourth specimen might be a hybrid be- 

 tween Hy. anstralis and Hy. melanochir; hence, 

 pigment comparisons were made prior to preser- 

 vation. There was more yellow on the anterior 

 edge of the anal fin in the small Hy. melanochir 

 than in the two Hy. australis. The fourth spe- 

 cimen was intermediate. Pigmentation in the 

 pectoral fin was most prominent in the Hy. mel- 

 anochir and the fourth specimen where the mel- 

 anophores formed a spot distally in the fin. The 

 pigment was distributed all over the fin in the 

 two Hy. australis. Scattered small melanophores 

 gave a mottled appearance to the lateral line 

 along the body in the Hy. melanochir. This pig- 

 ment was absent in both Hy. australis. A trace 

 of pigment was present in the fourth specimen. 



The three larger specimens had a more prom- 

 inent ridge in the middle of the upper jaw than 



did the small Hy. melanochir. The upper jaw 

 of the Hy. melanochir was distinctly shorter than 

 its width (width/length ratio 1.33), in agree- 

 ment with 35 Victorian specimens of the species 

 (0.92-1.49, mean 1.16). The two Hy. australis 

 had the upper jaw about as long as wide (ratios 

 0.99 and 0.96) as do 32 other Hy. australis (0.86- 

 1.29, mean 1.00). The fourth specimen was in- 

 termediate (ratio 1.23) between Eden specimens 

 of the two species but within the usual range of 

 Hy. melanochir (Figure 1). 



14 



E 

 E 



£12 



on 



10 



a 

 a 



.® 



• o 

 o 



o 



o o 



' . I. o 



©V ^^o\ 



o<- 



00° °n 00 





^••.* o* 



,8 8° oo 

 •o o , 

 o o' 



o 



o- ° 



_1_ 



10 12 14 



Upper Jaw Width (mm) 



16 



18 



Figure 1. — Relationship of upper jaw length to upper 

 jaw width in two species of Australian halfbeaks. Open 

 circles indicate Hyporhamphus melanochir; dots Hy. 

 australis. Four specimens from Eden, New South Wales 

 indicated by letters: a for Hy. australis; m for Hy. 

 melanochir; and h for Hy. australis X melanochir. 



Otoliths were extracted from all four speci- 

 mens while fresh and were examined shortly 

 thereafter by otolith specialist John E. Fitch, 

 who was told only that the four sets of otoliths 

 had come from some Australian halfbeaks. He 

 concluded that two sets (the Hy. australis) were 

 of one species, one set (the small Hy. melano- 

 chir) was of a second species, and the fourth set 

 was intermediate. Hy. aiistralis has a much 

 longer (relative to height) sagitta than Hy. mel- 

 anochir (Figure 2). Length divided by height 

 averages (left and right sagittae measured) 1.91 

 and 1.93 for the two Hy. aiistralis, 1.43 for the 

 Hy. melanochir, and 1.72 for the fourth speci- 

 men. Hy. australis has a more pointed rostrum 

 than Hy. melanochir, and has a vertical groove 

 near the rostrum on the external side that is 



319 



