scapula or coracoid, the uppermost always sutured to the 

 scapula; urohyal absent; no more than three pharyngo- 

 branchials present; fifth ceratobranchial usually tooth- 

 less, rarely with even a small patch of minute teeth; den- 

 taries and premaxillaries totaling either two or four 

 separate pieces; premaxillaries, if separate, articulated 

 to one another by prominent regular interlocking 

 emarginations; sphenotic relatively large and not con- 

 fined to the posterior wall of the orbit, but present on 

 both the lateral and dorsal surfaces of the skull as well; 

 first branchiostegal ray with its dorsal edge either not in- 

 turned at all and articulated to the ventral edge of the 

 ceratohyal or greatly inturned into a huge plate and ar- 

 ticulated to the medial surface of the ceratohyal; inter- 

 operculum with a ventral flange and a long posterior 

 shaft extending well behind the ventral flange and level 

 of the epihyal, except in molids in which the interoper- 

 culum is a short to long simple slender rod without a ven- 

 tral flange; pterotic not prominently prolonged postero- 

 ventrally as a stout shaft; epiotic placed more medially 

 on the top of the skull, always in contact with the 

 supraoccipital; exoccipital never in contact with the 

 frontal; frontal never in contact posteriorly with the 

 pterotic in the rear of the orbit, separated from it by the 

 sphenotic, while in some tetraodontins posterolateral 

 wings from the dorsal surface of the frontal make con- 

 tact with the pterotic on the top of the rear of the skull; 

 olfactory epithelium smooth, pitted or in parallel folds, 

 never in a rosette, the olfactory sac either above the sur- 

 face in a tube or tentacle with one or two nostrils, or at or 

 below the surface and rudimentary. 



SUPERFAMILY TETRAODONTOIDEA 



Comparative diagnosis (contrast with that of the 

 Moloidea). — Inflatable diverticulum of the gut present; 

 first branchiostegal ray with the dorsal edge inturned 

 and enormously enlarged into a more or less horizontal 

 pumping plate articulated to the medial surface of the 

 ceratohyal; air bladder well developed; three gills, not 

 greatly expanded dorsally; no gill slit between the gill- 

 less fourth and fifth arches and no gill rakers along the 

 posterior edge of the fourth arch and the anterior edge of 

 the fifth arch; no gill rakers along the anterior edge of the 

 first gill slit; pharyngobranchials with moderate to 

 minute teeth, and one sometimes toothless, the three 

 elements being those of the first to third arches (that of 

 the third sometimes absent); ceratobranchial and epi- 

 branchial sutured to one another; interhyal and dorsal 

 hypohyal often absent; teeth in biting edge of jaws 

 retaining much of their individual identity; basi- 

 sphenoid absent; caudal fin relatively normal, with 9 to 

 11 rays supported by variously consolidated and fused 

 but normal vertebral elements; most dorsal, anal, 

 caudal, and pectoral fin rays less extensively branched 

 but with a normal amount of cross-striations, these not 

 confined to only the distal ends of the rays; sesamoid ar- 

 ticular usually present; postcleithrum without an an- 

 teriorly directed process; four actinosts; supracleithrum 



less elongate, only its extreme proximal end articulated 

 directly to the pterotic; coracoid less long and slender, 

 with a posterodorsal prong below the lower actinost al- 

 ways developed to some degree; operculum and sub- 

 operculum of much greater complexity of structure and 

 lateral surface area; interoperculum with a ventral flange 

 and posterior shaftlike portion extending posteriorly well 

 beyond the level of the epihyal; basioccipital not 

 prolonged dorsally behind the exoccipitals, the exoc- 

 cipitals bordering all but the bottom edge of the foramen 

 magnum; exoccipitals with condyles and in contact with 

 the first vertebra, which articulates anteriorly with both 

 the basioccipital and exoccipitals; epiotic without any 

 kind of posterodorsal prolongation; pterotic not prolong- 

 ed posteriorly, not reaching posteriorly to the level of the 

 end of the basioccipital; bony canal, when present, for 

 the nerves and blood vessels running from the orbit to the 

 nasal region nearly always incomplete, surrounded by 

 the prefrontal laterally, above and below, but not 

 medially; palatine receiving its main support dorsally 

 either by a complex interlocking with the vomer and eth- 

 moid or by extensive suturing to the frontal; at least the 

 first three abdominal vertebrae with bifid neural spines 

 projecting dorsally or dorsolaterally on each side of the 

 neural arch; centra of at least some of the abdominal 

 vertebrae always with ventral or ventrolateral processes 

 of some sort, whether or not forming complete haemal 

 arches or zygapophyses; dorsal and anal fin rays not 

 widely separated from their basal pterygial supports by a 

 large block of cartilage; scales, when present, small to 

 large, the basal plates not forming a completely con- 

 tinuous covering over the entire body, and some of the 

 scales always forming prominent prickles or spines; one 

 or two nostrils in a prominent upraised sac or tentacle, or 

 a single minute nostril in a low tube; lateral line present, 

 whether conspicuous or inconspicuous, but nearly al- 

 ways clearly seen within 30 magnifications. 



