1129 ^ 
Order Keterosoniata 
Body asymmetrical, strongly compressed, precaudal region short. 
Cranium normal behind, mth twisted vertex in front to permit 2 eyes on 
same side, or one vortical end other lateral. Mouth more or less protrac~ 
tile, formed above on edges by premaxi1laries only. Interorbitol bar 
mainly formed by frontal of eyed side. Parietals separated by supraoccip- 
ital. Vertebral column of solid contra joined with arches. Pectoral arch 
joined to skull by forked post-temporal. Upper pharyngeals 4, third 
largest, much extended forward. Lowor pharyngeals separate. Air bladder 
absent in adult. Dorsal and anal long. Caudal with 17 rays, 15 branched, 
or fewer. Ventrals with 6 rays or less, thoracic or jugular, 
A large givoup of fishes, remarkable for the asymmettrical devel¬ 
opment of color on one side of the body. In the very young both sides of 
the body are alike, one eye is placed on each side, the cranium normal 
and the fish swims erect. 
