1. THERArON. 277 



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

 liameter of the cj-e ; the snout is a little longer. Praeoperciilum 

 I'ounded, with moderate dentieulations, gradually becoming larger 

 towards the angle. Operculuna with two spines, the lower of A^hich 

 is very long and strong. Spines of moderate strength ; the fouith 

 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. CaudaUs scarcely emarginate. Cheeks 

 witli five or six scries of scales. Coloration uioiform ; a black blotch 

 between the third and sixth spines. 

 India. 



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



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

 D, 1^. A. J. L. lat. 50. L. transv. 9/20. 



The height of the body is four times in 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. Pra?operculum rounded, 

 finely serrated ; prasorbital and coracoid indistinctly denticidated. 

 Operculum 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 roimded 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-k. Adult : skins. Gw^'dii- River. 



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

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

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

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

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

 terior margin of the ej'e. The pra^orbital is quadrangular, not much 

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

 stinctly denticidated. 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 priseoperculum. The naked margin of the 

 pracopcrculum is narrow, the angle rounded ; the posterior limb 

 finely serrated, and longer than the lower, wliich is entii-e. The 

 scales of the operclcs 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 veiy obtuse, the lower spinous and rather 

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

 lation ; the sujirascapula 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 fii'st is 



