182 Mr. G. A. Boulenger on the Stdwi-ders and 



II. Pr?emaxillaries not protractile ; scales usuallj- small or ab?ent ; body 

 more or less elongate ; dorsal tin elongate, single or divided, 

 withont free spines ; no free anal spines. 



A. Pseudobranchige present. 



Vertebrae without transverse processes ; soft dorsal 

 fin longer than the spinous ; pectoral fins high 

 up the sides 3. ScomhridcB. 



Vertebrae without transverse processes ; soft dorsal 

 fin shorter than the spinous, if the latter be 

 distinct ; pectoral fin low down the sides 4. TrichivridtP.. 



Vertebrae without transverse processes; soout pro- 

 duced into a spear o. Histioj^horidw. 



Vertebrae with transverse processes bearing the 

 ribs ; snout produced into a sword ; no 

 ventrals , G. Xiphiida;. 



Vertebrae without transverse processes ; gill- 

 membranes attached to isthmus ; dorsal and 

 anal fins formed of unartlculated, widely set 

 rays ; dentition very feeble 7. Luvarida;. 



B. Pseudobranchiae absent; no well -developed transverse processes 



to the praecaudal vertebris, the ribs and the epipleurals inserted 

 close together on the centra ; snout short and very deep. 



8. CoryphcenidcP. 



III. Praemaxillaries not protractile, or, if slightly protractile, scales 

 large ; dorsal and anal fins elongate, without distinct spinous 

 division ; most of the praecaudal vertebra with strong hiBma- 

 popbyseS; to which the ribs are attached .... 9. Bramida. 



Division III. Zeorhombi. 



Aberrant, strongly compressed Perciformes, with very 

 phort prgecaudal region, modified in the direction of the fiat- 

 fishes, culminating in asymmetrical forms, and characterized 

 "by the combination of an increased number (7 to 9) of 

 ventral rays, with absence of hypural spine (by which the 

 Berycidse are excluded), or by asymmetry of the skull in 

 the forms in which the spine of the ventral fin has been lost. 

 Among the symmetrical forms, the existing Zeidje agree 

 with the Berycidas in having more than five soft rays to tlie 

 ventral fins^ and are probably derived, together with the 

 Eocene Amphistiidse, from some common ancestral group 

 still to be discovered in Cretaceous beds. These Zeidai have 

 much in common with the Pleuronectidaj * and might be 

 regarded as forming part of the family out of which the 

 latter have sprung, were it not that they have lost the last 

 half-gill. Ampktstium is probably more nearly related to 

 the Pleuronectidse, which may have been directly derived 

 from the family of which it is as yet the only known 

 representative f. 



* Cf. Thilo, Zool. Anz. 1902, p. 305. 



T Cf. Boulenger, Ann. & ^lagT Nat. Hist. {7) x. 1901!, p. 205. 



