368 FISHES. 



Second Family — Saurid.e. 



Body oblong, with ganoid scales; vertebrcc not completely 

 ossified ; termination of the vcrtehral column homocerccd ; fins 

 generally loith fulcra. Maxillary composed of a single piece ; 

 jaws loith a single scries of coniccd pointed., teeth. Branchioste- 

 gcds numerous, enamelled, the anterior hroad gidar plates. 



Extinct. Numerous genera occur in Mesozoic formations ; 

 one with the widest range is Semionotus, with distichous 

 fulcra, from the Lias and Jura ; EugnedJins, witli large 

 posteriorly serrated scales, and fulcra on nearly all fins ; 

 Ccjdienoplosus from the Upper Lias ; Afacrosemiics from the 

 Oolite ; FrojJterus, Op)hiop)sis, Pholidop)horus, Bleuropholis, 

 Pachycormus, Oxygnathus, Ptycholepis, Cooiodus, Eulepidotus, 

 Lophiostomus, etc. 



Third Family — Stylodoxtid^. 



Body rhombic or ovate, with ganoid scedes ; vertebrce not 

 completely ossified ; termination of the vertebral column homo- 

 cerccd ; fins with fulcra. Maxillary composed of a single piece ; 

 jaws with several series of teeth, the outer ones equal, styliform.. 

 Dorsal fin very long, extending to the caudcd. Branchiostegals 

 numerous. 



Extinct. Tetragonolepis from the Lias (see Fig. 103, p. 

 207). 



Fourth Fa^mily — SPHiEEODONTiDyE. 



Body obhng, with rhombic ganoid scedes ; vertebrm ossified, 

 but not completely closed ; homocercal ; fins with fulcra. 

 Maxillary composed of a single piece; teeth in several series, 

 obtuse ; those on the jjcdcdc globular. Dorscd and ancd fins short. 

 Branchiostegcds. 



Extinct. The type genus of this family is Lepidotus, so 

 named from its large rhombic, dense, and polished scales. 



