12 MEMOIRS OF THE QUEENSLAND MUSEUM. 



Nostrils subequal and approximate, situated in front of the upper half of the 

 eye, the anterior valvular. Eyes small and superolateral, wholly anteromedian. 

 Preorbital, suborbital, and subopercular bones more or less finely serrulate; 

 preopercle serrated, the teeth of the lower limb antrorsely directed ; operele with 

 two spines, the lower the longer, and a wide naked membranous flap ; posttemporal 

 exposed and serrulate. One dorsal fin, with x 10 or 11 rays, the spines strong 

 and pungent, the spinous portion longer than the soft. Caudal rounded, with 17 

 rays, the upper and lower simple, the others branched. Anal fin short, with iii 7 

 to 9 rays, the second spine longer and much stronger than the third. Pectoral 

 rounded, with 15 to 17 rays, the middle upper ones the longest. Ventrals inserted 

 below the pectoral-base, close together, with a strong spine and 5 soft rays, the 

 outer of which is produced in, a filament. Gill-openings wide; gill-membranes 

 separate, free from the isthmus ; branchiostegals seven^ ; pseudobranchiae present ; 

 gills four, a slit behind the fourth ; gill-rakers rather long and stout, in moderate 

 number. Air-bladder present, large and simple. Pharyngeal bones densely 

 armed with minute conical teeth. Stomach c^cal; intestinal canal biconvolute; 

 pyloric appendages in moderate number. Premaxillary processes not extending 

 to the frontals, parietal and supraoccipital bones not extending to between the 

 postfrontal processes; supraoccipital crest strong, not produced on the frontals. 

 Vertebrae 11 + 15 = 26. 



A monotypic genus, the single species inhabiting the rivers of the eastern 

 half of Australia northward to about the Tropic of Capricorn. Not found in the 

 cismontane rivers of Victoria and New South Wales southward of the Clarence 

 Watershed. 



PLECTROPLITES AMBIGUUS (Richardson). 

 Batnia ambigua Kichardson, Zool. Erebus & Terror, ii, lehth., pt. 1, 1848, p. 25, pi. xix. 



Dules ambiguus Giinther, Brit. Mus. Catal. Fish., i, 1859, p: 270; Klunzinger, Sitz. Akad. 

 Wien, Ixxx, 1880, i, p. 348. 



Ctenolates macqiiarien.sis Giinther, Proe. Zool. Soc. London, 1871, p. 320, pi. xxxiii. 



Bules auratws Castelnau, Proe. Zool. & Acclim. Soe. Vic, i, 1872, p. 55. 



Dules flavescens Castelnau, Ees. Fish. Austr., 1875, p. 10. 



Ctenolates ambiguus Giinther, Zool. Challenger, i, 1880, Shore Fish, p. 32; Macleay, Proe. 

 Linn. Soc. N. S. Wales, v, 1881, p. 354; Woods, Fish & Fisher. N. S. Wales, 1882, p. 103; 

 McCoy, Prodr. Zool. Vic, dec. ix, 1882, p. 15, pi. Ixxxiv; Ogilby, Catal. Fish. N. S. Wales, 

 1886, p. 11; Lucas, Trans. Roy. Soc. Vic. (2) ii, 1890, p. 18; Ogilby, Edib, Fish. 

 N. S. Wales, 1893, p. 22, pi. v; Boulenger, Catal. Percif. Fish., i, 1895, p. 134; O'Connor, 

 Proe Eoy. Soc. Queensl., xii, 1897, p. 109 ; Zietz, Trans. Roy. Soc. S. Austr., 1902, p. 265. 



Ctenolates flavesce^is Macleay, ibid., p. 355; Ogilby, Catal. Fish, N. S. Wales, 1886, p. 11. 



Plectroplites ambiguus Bleeker, Arch. Neerl. Sci. Nat., xi, 1876, p. 267; Waite, Syn. Fish. 

 N. S. Wales, 1904, p. 26; Stead, Fish, Austr., 1906, p. 97; id., Edib. Fish, N. S. Wales, 

 1908, p. 55, pi. xxiii; Zietz, ibid., xxxiii, 1909, p. 268; Eoughley, Fish. Austr., 1916, 

 p. 67, pi. xvii. 



'Boulenger (Ice, eit,) gives the number of branchiostegal rays as "six or seven," 

 I have at different times examined quite a large number of specimens, and have invariably 

 found seven. This should, therefore, be taken as the normal number. 



