SYSTEMATIC RELATIONS OF FISHES. 591 
PHYSOCLYSTI. 
The following is an analytic synopsis of the orders. They all 
have the parietals entirely separated by the supra-occipital, and 
. lack the pracoracoid ; the symplectic is present, except in Ostra- 
cium, where it is not ossified. 
Scapular arch not suspended from the cranium. 
Superior branchihyals and pharyngeals developed ; inferiors and 
maxillary distinct. 15. Opisthomi. 
. Scapular arch suspended from the cranium. 
I. Ventral Fins Abdominal. 
Branchial arches well developed, the bones present, except 
fourth superior pharyngeal; third much enlarged; inferior pha- 
ryngeals distinct. 16. Percesoces — Mullet, ete. 
Third and fourth superior pharyngeals much enlarged, inferior 
pharyngeals, codssified. 17. Synentognathi—Soft gar 
Superior branchials and pharyngeals reduced in number ; infe- 
riors separate; interclavicles present. 18. Hemibranchi— Pipe 
fishes. 
Superior branchihyals and pharyngeals, and basal branchihyals 
wanting; gills tufted. 19. Lophobranchi—Sea horse. 
II. Ventral Fins Thoracic or Jugular. 
First vertebra united to cranium by suture; epiotics united 
behind superoccipital ; basal pectoral radial bones elongate. 20. 
Pediculati— Goose Fish, etc. 
Posterior cephalic region normal, anterior twisted so as to bring 
both orbits on one side; inferior pharyngeals distinct. 21. He- 
terosomita — Flounders 
Cranium normal ; ‘he sieemuciilaries usually codéssified with the 
anait behind, and the dentary with the pioen: pharyn- 
geal bones distinct. 22. Plectognathi— File 
Cranium normal; bones of the jaws anion ; ental pharyn- 
geal bones distinct. 23. Percomorphi— Perch. 
Cranium normal; bones of the jaws distinct; third superior 
pharyngeal much enlarged, articulating with cranium; inferior 
pharyngeals coéssified. 24. Pharyngognathi — Burgall, Parrot 
Fish. ` 
