1. THEHAPON. 277 



the head 3|. The interspace between the eyes equals nearly the 

 liameter oi the eye ; the snout is a Kttle longer. Praeoperculiun 

 rounded, with moderate denticulations, gradually becoming larger 

 towards the angle. Operculum with two spines, the lower of which 

 is very long and strong. Spiaes of moderate strength ; the fourth 

 of the dorsal more than one-half the length of the head, and the 

 twelfth much longer than the preceding. The third spine of the 

 anal longer than the second. Caudalis scarcely emarginate. Cheeks 

 with five or six series of scales. Coloration uniform ; a black blotch 

 between the third and sixth spines. 

 India. 



a, Adxilt. India. Old Collection, with the name of Perca argentea. 



8. Therapon xinicolor. (Plate XVI. fig. A.) 

 D. }?. A. J. L. lat. 50. L. transv. 9/20. 



The height of the body is four times iji the total length, the length 

 of the head 4^ ; the interspace between the eyes is more than their 

 diameter, and the snout is still longer. Praeopereulum rounded, 

 finely serrated; praeorbital and coracoid indistinctly denticulated. 

 Opercidimi with two spines, the lower of which is slightly pointed. 

 Spines of the dorsal rather feeble ; the sixth is the longest, and 3| in 

 the length of the head. Caudal truncated, with rounded angles 

 Cheeks with small scales, forming many series. Greyish, each scale 

 with darker margin. 



Fresh waters of New South Wales. 



a-d. Adult : skins. Head of Mosquito Creek, near Darling Downs. 

 e-Jc. Adult : skins. Gwydir River. 



Description. — The height of the body is one-fourth of the total 

 length. The head is sKghtly compressed, its width between the 

 orbits being one-fourth of its length, -vvhieh is 3^ in the total. The 

 upper surface of the head is flat and entirely scaleless. The snout 

 is of moderate length, the upper maxiUfity reaching beyond the an- 

 terior margin of the eye. The praeorbital is quadrangular, not much 

 narrower posteriorly than anteriorly ; it has the lower edge indi- 

 stinctly denticulated. The eye is situated high up the sides, rather 

 small, taking one-sixth of the length of the head. The scales of the 

 cheeks are small, and arranged in about nine series between the 

 orbit and the angle of the prseoperculum. The naked margin of the 

 praeopereulum is narrow, the angle rounded ; the posterior Hmb 

 finely serrated, and longer than the lower, which is entire. The 

 scales of the opercles are intermediate in size between those of the 

 cheek and of the body. The operculum has two points, with a notch 

 between ; the upper is very obtuse, the lower spinous and rather 

 prominent. The sub- and interoperculum do not show any denticu- 

 lation ; the suprascapula is not visible, whilst the coracoid is very 

 broad, scaly, and denticulated at its posterior margin. 



The spines of the dorsal fin are feeble and rather low : the first is 



