SCALES OF SOME AUSTBALIAN FISHES.— COCEEBELL. 4£ 



than long; lower margin wavy but not erenate; laterobasal corners obtuse, but 

 often projecting, the lateral margins then concave ; no radii ; circuli rather coarse r 

 transverse as far as an obtuse ridge which extends on each side from nucleus to 

 laterobasal corner, then bending and ascending vertically at sides; nucleus just 

 below the apical margin; margin with large, very sharp teeth (about 24), and 

 rows of similar teeth usually (not always) present in the submarginal region, 

 whence they are easily deciduous. There is no ctenoid patch of the ordinary type. 

 8. multifasciatus, as figured by Giinther, has similar teeth. 



This is a very remarkable type of scale, rather suggestive of Percopsis. 

 In Columbia transmontana (U. S. Nat. Mus.) the scales are very broad, and have 

 a subapical nucleus, and a single (never more than one) row of large and sharp 

 apical teeth (about 20-24) ; they also are without radii. The scale of Columbia 

 is much broader than that of Scatophagus, the sides are very much shorter, and 

 the circuli are not so dense. 



PLATACID.E. 



Platax teira Forskal. Queensland. Scales subquadrate, as broad as 

 long, or broader than long, diameter about 2|-3 mm., peculiar for the contracted 

 base, so that the sides converge downwards; laterobasal corners very obtuse; 

 basal radii 3 or 4, very distinct, but close together ; circuli fine, normal ; nucleus 

 subapical, just below the ctenoid patch, which is only 3 or 4 rows deep ; marginal 

 teeth long and sharp ; submarginal elements shaped like tree-stumps, distinctly 

 longer than broad. 



This resembles Scatophagus in the subapical nucleus, but is otherwise 

 very different. Some scales of Pomacanthus arcuatus show the contracted base 

 very well. 



CH^ETODONTID^. 



The species now before me may be separated into three groups as follows : — 



Median ribs of apical teeth extending as continuous rods to base of ctenoid area 



Pomacanthus arcuatus. 

 Ctenoid patch large, with the elements separate, as usual in Aeanthopterygian scales . . 1. 



1. Scales much longer than broad, parallel-sided; nucleus subapical, just below the ctenoid 

 patch; basal radii 6 to 8; circuli excessively fine; ctenoid elements like those of 

 Clicetodon (Queensland) . . . . . . . . . . Microcantlius strigatus Langsd. 



Scales not longer than broad, usually broader than long Clicetodon, Chehnon, and Heniochus. 



It is impossible to find satisfactory characters for the separation of the 

 species of Chcetodon, Chelmon, and Heniochus. The ctenoid elements of Chelmon 

 are coarser than those of Heniochus, but the structure is the same. The scales 

 of these fishes must be easily deciduous, judging from the large number of 

 latinucleate ones. 



