Cockerell: Scales of Characinid Fishes. 99 



Pyrrhulinin^. 

 Pyrrhnlina filamentosa Cuvier & Valenciennes has been examined. 

 The form of the scales (with strong laterobasal angles) and their 

 strong and characteristic radial sculpture, are entirely those of the 

 Pcvcilohrycon-Nannostomiis group. The apical circuli are longi- 

 tudinal, and the apica' margin has low and inconspicuous but gen- 

 uine crenulations. With a high power it is noted that the dense 

 transverse basal circuli in P cccUohrycon ocellatus are moniliform 

 broken into innumerable short pieces, averaging perhaps twice as 

 long as Avide. In Nannostomns marginatus and the Pyrrhulina 

 these circuli are broken here and there, but are essentially entire. 

 Thus, going on the scales alone, we should reach a different classi- 

 fication from that current, as follows: 

 I. Characidium. 



( P Cecil ohrvcon. 



Nannostomus. 



3- \ 



Pyrrhulina. 



Aphyocharacin^. 



Aphyocharax ery hrurus Eigenmann (cotype) is shown in Plate XXVI, 

 fig. 5. The shape resembles that of Pcecilohrycon, Pyrrhnlina, etc., 

 but the strong radial system is wanting, the radii being really reduced 

 to a long U-shaped figure pointing apically, as the figure well 

 shows. The figure does not show that the base of this U is finely 

 reticulated, and that the field between its arms has a fine longitudinal 

 striation, like that in the interradial field of Characidium Uennoides. 

 The widely spaced apical circuli, wholly longitudinal, simulate radii. 

 All this could well be a modification of the Characidium type. 



Cheirodon insignis Steindachner was figured in Smiths. Misc. Coll., 

 vol. 56, No. I, p. 3. It is a much weaker form of scale, with the 

 sculpture evanescent apically. 



Crenuchin^. 



The two known species have been examined. 

 Crenuchus spilurns Giinther. Scale broad, with the nucleus far 



basad; apical circuli longitudinal, widely spaced; apical radii about 



six. 

 P(Ecilocharax hovallii Eigenmann. Scale of the same character, but 



not so broad. Compared with Aphyocharax erythrurus, these scales 



differ conspicuously by the gently convex base, without the notch 



