112 MEMOIES OF THE QUEENSLAND MUSEUM. 



The protrusion of the eyeball in fishes, a disease commonly known as " Pop-eye," 

 has formed the subject of a very valuable paper by Professor C. Coleridge Farr.^ His 

 investigations, which were based on the eggs and young of trout in the Canterbury 

 artesian water system, practically proved that the eyes protruded as a result of 

 excessive gas contained in the water, and he expressed the opinion that the effect was 

 identical with that observed in the Corella bore fishes. Under these circumstances, we 

 see no reason to accept Mr. Stead's suggestion that these fish came up the bore, but 

 assume that they were merely aestivating somewhere in its vicinity, and upon being 

 again vivified by the bore water, came under the influence of its contained gases 

 and so developed pop-eye. 



Uses : — ^Though rather small for general table use this species attains a weight 

 of half a pound, and is of good flavor as a pan-fish, while with a light rod and the 

 finest tackle it gives fair sport, fighting gamely for its life when hooked. 



Range ; — This fish is very widely distributed throughout subtropical and 

 tropical Australia, being found practically everywhere from lat. 30° 8. northward 

 to Cape York and westward to at least the upper waters of the Murchison, whence 

 the late Mr. Alexander Morton brought two small specimens many years ago. 

 Specimens are in the Australian Museum from King Sound, North-Westem Austraha, 

 which were collected by Mr. J. Cairn in 1886. 



Illustration : — Our figure is taken from a fine specimen collected by Dr. Thomas 

 Bancroft at Eidsvold on the Burnett. 



THERAPON BID Y AN A Mitchell. 

 SILVER PERCH. 



Acerina (Cernua) bidyana Mitchell, Three Exped. Int. Eastern Austr., i, 1838, p. 95, pi. viii. 



Datnia elliptica Richardson, Zool. Erebus and Terror, Ichth., 1848, p. 118, pi. lii, fig. 4-8. 



Therapon ellipticus Giinther, Brit. Mus. Cat. Fish., i, 1859, p. 276 ; Klunzinger, Arch, fiir Naturg., 

 xxxviii, i, 1872, p. 21 ; id., Sitzb. Akad. Wiss. Wien, Ixxx, i, p. 350 ; Castelnau, Proc. Zool. 

 Soc. Vict., ii, 1873, p. 127 ; Macleay, Proc. Linn. Soc. N. S. Wales, v, 1881, p. 3G3 ; Ogilby, 

 Ed. Fish. N. S. Wales, 1893, p. 28, pi. vi ; Waite, Rec. Austr. Mus., iii, 19UU, p. 210. 



Terapon ellipticus Waite, Mem. N. S. Wales Nat. Club, No. 2, 1904, p. 33 ; Stead, Ed. Fish. N. S. 

 Wales, 1908, p. 73, pi. xlii. 



Therapon ni-r'^ Castelnau. Proc. Zool. Soc. Vict., i, 1872, p. 59 ; id., ibid., ii, 1873, p. 38 ; Macleay, 

 ibid., p. 365 ; id., ibid, ix, 1884, p. 12 ; Ogilby, Cat. Fish. N. S. Wales, 1886, p. 11 , Lucas, 

 Proc. Roy. Soc. Vict. (2), ii, 1890, p. 19. 



Therapon richardsoni Castelnau, Proc. Zool. Soc. Vict., i, 1872, p. 60; Macleay, ibid., p. 364; 

 Ramsay, Proc. Linn. Soc. N. S. Wales, vi, 1882, p. 832 ; Ogilby, ibid., p. 11 ; Lucas, ibid. ; 

 Kent, " Gt. Barrier Reef," 1893, pp. 282, 369. 



Therapon madeayana Ramsay, Proc. Linn. Soc. N. S. Wales, vi, 1882, p. 831 ; Macleay, ibid., ix,. 

 1884, p. 12 ; Ogilby, ibid., p. 12. 



Therapon bidyana McCuUoch, Rec. Austr. Mus., ix, 1913, p. 359 ; id., Proc. Linn. Soc. N. S. Wale?^ 

 xl, 1915, p. 262, pi. xxxvi, fig. 1. 



D. xii 12-13 ; A. iii 8-9 ; P. 17 ; V. i 5 ; C. 17. 75-89 scales between the origin 

 of the lateral line and the hypural joint counted below the lateral line, and 82-92 

 above it ; 13-14 between the lateral line and the middle of the spinous dorsal. Cheek- 

 scales in 8-10 rows. 



« Coleridge, Rept. 13th Meeting Austr. Assn. Adv. Sci., 1911 (1912), p. 354. 



