400 FISHES. 



rather short or of moderate length. Praeoperculum without spine. 

 Scales of moderate size. 



Four species are known from the tropical Indo-Pacific. 

 H. macrolepidotus is one of the most common fishes of that 

 area ; the species figured {H. varius) retains in a conspicuous 



^ 



^■" 

 ^ 





Fig. 169. — Heiiioclius varius. 



manner horn-like protuberances on bones of the head, with 

 which the you.ng of all the species of this genus seem to be 

 armed. 



HoLACANTHUS. — Prfeoperculum with a strong spine at the 

 angle. One dorsal, with from twelve to fifteen spines. Scales of 

 moderate or small size. 



Forty species are known, which, in their geographical 

 distribution accompany, and are quite analogous to, the 

 ChEetodonts. One of the most common and most beautiful 

 is called " Emperor of Japan " by the Dutch, M'hich name 

 has been adopted by Bloch for its specific designation, 

 Holacantlius imperator. Its body is blue, longitudinally tra- 



