Order SYNENTOGKA.THI 
Maxillary near or close to premaxillary, again solidly 
united though with distinct sutures. Articular bone of lower jaw 
with small supplemental bone. Lower pharyngeal bones completely united. 
Branchiostegals 9 to 15. Vertebrae numerous, 45 to 70, abdominal more 
numerous than caudal. Ribs begin on first vertebra. Scapula suspended 
to cranium by posttemporal bone, whioh is slender and forked. Air bladder 
large. Intestinal canal simple, without pyloric appendages. Lateral 
line low or along lower side of body, concurrent with ventral profile 
of body, of peculiar structure and often not quite reaching caudal. Pins 
without spines. No adipose fin. Ventrals abdominal, rays more than 5. 
A large group of fishes, well represented in all tropical seas. 
According to Regan they comprise an isolated assemblage without evident 
relationship to any other fishes though showing certain affinities with 
the toothed minnows or cyprinodonts. In earlier taxonomic arrangements 
of fishes the Synentognathi marked the beginning of the series Physoclisti , 
characterized by the absence of a duct connecting the air bladder with the 
alimentary canal. In contrast were the more primitive groups of bony 
fishes or Physostomi , all with a persistent duct. 
Analysis of Suborders 
er. Mouth usually large; third upper pharyngeals moderately 
enlarged, separate, fourth usually present; scales very 
small------ - - — --Scambresocoidea. 
&. . Mouth small; third upper pharyngeals strongly enlarged, 
together forming somewhat convex ovoid plate; scales 
rather large---———-Exocoetoidea . 
