400 



FISHES. 



rather short or of moderate length. Prseopercukim without spine. 

 Scales of moderate size. 



Four species are known from the tropical Indo-Pacific. 

 H. macrolcpidotus is one of the most common fislies of that 

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



Fig. 169. — Heniochus variiis. 



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

 which the young of all the species of this genus seem to be 

 armed. 



HoLACANTHUS. — Prwoperculum 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 

 Chsetodonts. One of the most common and most beautiful 

 is called " Emperor of Japan " by the Dutch, which name 

 has been adopted by Bloch for its specific designation, 

 Holacanthus imperator. Its body is blue, longitudinally tra- 



