THE SQUIRREL-FISHES 



Family XXX. Holocentridcz 



BODY oblong or ovate, moderately compressed, covered with 

 very strong ctenoid or spinous scales; head with large muciferous 

 cavities; eyes lateral, very large; preorbital very narrow; mouth 

 moderate, oblique; premaxillaries protractile; maxillary very large, 

 with supplemental bone; bands of villiform teeth on jaws, vomer 

 and palatines; opercular and membrane bones of head generally 

 serrated or spinescent along their edges; branchiostegals 8; gill- 

 membranes separate, free from the isthmus ; pseudobranchiae present; 

 no barbels; sides of head scaly; lateral line present; dorsal fin very 

 long, deeply divided, with about 1 1 strong spines depressible in 

 a scaly groove; anal with 4 spines, the third longest and strongest; 

 ventrals thoracic, with one spine and 7 rays; caudal deeply 

 forked, with sharp rudimentary rays or fulcra at base; vertebras 

 about 27; pyloric coeca 8 to 25; air-bladder large, sometimes con- 

 nected with the organ of hearing. General colour red. Genera 

 4, species about 70, gaily-coloured inhabitants of tropical seas, 

 abounding about coral reefs. Only 4 genera and about 12 species 

 in our waters. 



a. Preopercle without conspicuous spine at its angle. 



b. Scales very large and rough, about 30; Ostichthys, 264 



bb. Scales moderate, 35 to 45 ; ." Myrtpristis, 265 



aa. Preopercle with a conspicuous spine. 



c. Suborbital arch simply serrated, scales moderate. 



d. Mouth moderate; lower jaw slightly included, its length less 



than half head ; Holocentrus, 265 



dd.- Mouth very large; lower jaw projecting, its length more 



than half head ; Flammeo, 266 



cc. Suborbital arch armed with three long spines curved for- 

 ward Plectrypops, 267 



The genus Ostichthys is known by its very large scales. The 

 single species, O. trachypomus, is found only in the West Indies, 

 particularly about Cuba, and even there it appears to be rare. 

 Colour, carmine red, darker above; side with about 10 alternate 

 streaks of deep red and rose; fins all red. 



264 



