XXI MALACOPTERYGII 545 



3. Interoperoulum normal ; basis craiiii simple. 

 Maxillary large, toothed ; praecaudal vertebrae without well-marked parapo- 

 physes ; scales cycloid or absent ; adipose dorsal fin present or absent 



19. Stomiatidae. 

 Mouth small, toothless ; vertebrae with strong parapophyses ; head and body 



covered with spiny scales . . .20. Gonorhynchidae. 



Mouth small, toothless ; no sympleotio ; head and body naked 



21. Gromeriidae. 



Fam. 1. Pholidophoridae. — Margin of the upper jaw formed 

 by the praemaxillaries and the mamillaries, the latter large and 

 loosely attached ; teeth small and conical. Parietal bones separ- 

 ating the supraoccipital from the frontals ; opercular bones well 

 developed. Vertebral centra never advanced beyond the annular 

 stage ; ribs delicate ; no fused or expanded haemal arches at the 

 base of the tail ; no epipleurals or epineurals. Fin-fulcra present, 

 but usually small ; dorsal and anal fins small, the former above or 

 behind the ventral fins, which are small or may be absent. Scales 

 ganoid, rhombic, those on the flanks united by peg-and-socket 

 joints. 



This family, which appears to me to be related to the 

 Dapediidae, is provisionally placed here by A. S. Woodward on 

 account of its resemblance to the Leptolepididae, but it is not yet 

 quite clear that the mandible was destitute of splenial and coronoid 

 elements, while the bones at the base of the pectoral fin have not 

 hitherto been observed. The principal genera are Fholidophorus, 

 ranging from the Upper Trias to the Purbeck ; Thoracopterus, 

 from the Upper Trias ; and Pleuropholis, from the Upper Jurassic. 

 The species of Plwlidophorus are very numerous in the Jurassic 

 period, and Woodward has observed that the scales of the later 

 species are more elaborately ornamented than those of earlier date. 



Fam. 2. Archaeomaenidae. — Distinguished from the pre- 

 ceding by the thin, cycloid scales. Conspicuous obtuse ridge- 

 scales are present along the dorsal and ventral lines. Archaeomenes, 

 from the Jurassic (?) of New South Wales. 



Fam. 3. Oligopleuridae. — Characters as in Pholidophoridae, 

 but scales cycloid and vertebrae completely or nearly completely 

 ossified. 



Oligopleurus, from the Jurassic of England and France ; Oeno- 

 scopus, from the Jurassic and Cretaceous of France, G-ermany, and 

 Italy ; and Spathiunis, from the Cretaceous of Mount Lebanon 

 and Dalmatia. 



VOL. VII 2 N 



