PERCIFORMES 



439 



ac 



FIG. -T.O. 

 MiiHiii'iiiitlni.-: 1-1,11, 1'ni-i fiki'his, Blkr. (After Day, Fishes of India.) 



Family OSTRACIOXTIDAE. 'Trunk'- or ' Coffer -Fish,' with long 

 narrow teeth. The carapace 

 has an almost vertical front edge, 

 angular sides, and often large 

 frontal and anal horns. 



Ostracion, L. ; tropical seas ; 

 Eocene, Europe. Aracana, Gr. ; 

 Lactophrys, Sw. tropical seas. 



BRANCH 2. TRIODONTES. 

 Family TRIODONTIDAE. A family 

 intermediate between the first 

 and third sub-groups, whose exact 

 position it is difficult to deter- 

 mine. The teeth coalesce into a 

 beak, single below but paired 

 above. The spinous dorsal and 

 the pelvic fins have disappeared, 

 there is a dilatable oesophageal 

 sac. Yet a movable pelvis is 

 present as in the Balistidae, which 

 they resemble in many characters 

 of the skeleton. There are twenty 

 vertebrae, and the body is covered 

 with small spiny plates. 



m j -rr - -n T T ClMomycterus reticulatus, L. Porcupine fish; 



1 notion, Kemw. ; E. Indies. from specimens in British Museum. Vertical 



"RRVX T PII 1 Pvurv/Ynrwrira median section of both jaws, a.c, alveolar cavity 



* ' TES - in which young teeth develop; i.o.t, grinding 



There are no normal Scales, no surface formed by inner set of old tooth-plates ; 



dorsal spinous fin, no pelvic fin 



FIG. 451. 



