398 



FISHES. 



Extinct representatives of this family are not scarce at 

 Monte Bolca and in other tertiary formations. All, at least 

 those admitting of definite determination, belong to existing 

 genera, viz. Holacanthvs, Pomacanthus, U^yJiippitmi, Scato- 

 'pliagvs. Very singular is the occurrence of Toxotcs in the 

 Monte Bolca strata. 



The following genera have no teeth on the palate : — 



Ch.'ETODGN. — One dorsal fin, without any notch in its upjier 

 margin, and with the soft and spinous poi'tions similarly developed; 

 none of the spines elongate. Snout short or of moderate length. 

 Prseoperculum without, or Avith a fine, serration, and without spine 

 at the angle. Scales generally large or of moderate size. 



Seventy species are known from the tropical parts of the 

 Atlantic and Indo-Pacific, nearly all being beautifully orna- 

 mented with bands or spots. Of the ornamental markings a 

 dark or bicoloured band, passing through the eye and ascend- 

 ing towards the back, is very generally found in these fishes ; 

 it frequently occurs again in other marine Acanthoptery- 

 gians, in which it is not rarely a sign of the immature 

 condition of the individual. The Cha?todonts are most 



Fig. 167. — Cliretoilou ephippiuiii. 



numerous in the neighbourhood of the coral-reefs of the Indo- 

 Pacific, the species figured (C. ejiJiippiiim) being as common 



