Cockerell: Scales of Characinid Fishes. Ill 



though the circuli are much less dense, and there are no radii, there 

 is quite a close resemblance to Chalcinus elongatns. We seem to get 

 a hint here of how a Serrasalmonine type of scale may be modified 

 into one more characteristic of the S. American Characinidie in 

 general. 

 Acanthocharax microlcpis Eigcnmann. Scales extremely broad, length 

 about one and one-third mm., breadth about two and one third mm.; 

 sculpture as in Cheirodon insignis or Hemigrammus orthiis, except 

 that the circuli are more numerous, and there are no radii whatever. 



Hydrocynin.e. 



Hydrocynns cuvieri (Agassiz). Small round scales resembling those of 

 the Serrasalmoninae, but the strong circuli are only moderately 

 dense, and in the apical field are irregular and much wider apart; 

 there are also a few strong radii, more or less in the form of a cross 

 or an X, usually two being basal. The nucleus is central, or nearly so. 

 A distinct type. 



The scale of Luciocliarax was figured by Bean in Proc. U. S. Nat. 

 Mus., 1908. It is entirely difTerent from that of Hydrocynus, but is 

 extraordinarily like that of the African PhractolcEtnus ansorgii Bou- 

 lenger. The fishes Luciocharax and Phractolcr?nus are of course 

 totally different. In the scale of Luciocharax we have something 

 wanting in the African Characinid fauna — a connecting link between 

 the Alestiform and Distichodontine types of scale. 



Acestrorhamphin.e. 

 Acestrorhynchus microlepis (Schomburgk) and .4. falcatiis (Bloch) 

 have small round scales, much like those of the Serrasalmonines, but 

 with the larger nucleus subbasal, and the circuli failing apically, the 

 innermost meeting at a wide angle. Plate XXV", fig. 7 shows A. 

 microlepis, drawn by Miss Evelyn Moore. 



Erythrinin^. 



These all have a purplish pigment on the exposed part of the scale 

 (very strong and dense in Iloplias macro phthalmus) ; the same sort 

 of thing is seen in Leporiniis and Characidium. 



Erythrinine scales are cjuite large, about as broad as long (broader 

 in Iloplerythrinus), the laterobasal angles approximately right angles, 

 the basal margin usually wavy or crenate, the median notch often 



