SUB-CLASS V 



GANOIDEl 



71 



Strepsodus, Young {Deiidroptychius, Young ; Archichthys, Hanc. and Atth.). 

 Large and medium- sized fishes with slender and somewhat curved teeth, 

 which are not compressed to sharp edges. S.' sauroides, Binney sp., from Goal 

 Measures of England, Scotland, and Ireland. Other species from Lower 

 Carboniferous of Scotland, Ireland, and Nova Scotia. 



Ehizodopsis, Young {Dittodus, Ganolodus, Characodus, Gastrodus, Owen), 

 (Fig. 128). Scales oval, with an extremely thin layer of punctate ganoine. 

 Teeth round in section, smooth. Vertebral axis with ring vertebrae. The 

 small type species represented by fine examples in the English Goal Measures. 

 Fragments in the Goal Measures of Silesia, Nova Scotia, and Illinois. 



Gyroptychius, M'Göy ; Tristichopterus, Egerton ; Eusthenopteron, Whiteaves ; 

 Polyplocodus, Pander ; Sauripterus, Hall. Devonian and Old Red Sandstone ; 

 Europe and North America. 



Family 3. Osteolepidae. Smith Woodward. 



Body slender, covered with rhomhic ganoid scales. Bing vertebrae at least in the 

 caudal region. Baired fins with a short, obtuse lobe. Teeth conical, only externally 

 folded at the base, as in Bhizodontidae. Devonian and Garboniferous. 



Osteolepis, Ag. {Tripterus, Triplopterus, M'Goy), (Fig. 129). Granial roof 

 bones in advance of the parietals fused into a continuous shield, pierced by a 



Fig. 12y. 

 Osteolepis viacrolepidotns, Ag. Lower Old Red Saiidstone ; Scotland (restoration after Pander). 



present. 



Scales 



Pander. 



Lower 



median frontal (pineal) foramen. An anterior median jngular plate 

 Teeth round in section. First dorsal fin in front of the pelvic pair. 

 smooth and punctate. 0. macrolepidolus, Ag., and 0. microlepidotus, 

 Lower Old Red Sandstone ; Scotland. 



Thursius, Traq. As Osteolepis, but first dorsal opposite pelvic fins. 

 Old Red Sandstone ; Scotland. 



Diplopterus, Ag. Lower Old Red Sandstone ; Scotland. , 



MegalicMhys, Ag. {Centrodus, M'Goy ; Bhomboptychius, Young ; Edosteorhachis, 

 Gope). Granial roof bones in advance of the parietals rarely fused into a 

 continuous shield, without a median frontal foramen. 

 Teeth round in section. First dorsal fin nearly opposite 

 the pelvic pair. Scales smooth and punctate. Garboni- 

 ferous of Great Britain and North America. Lower 

 Permian of Texas. M. hibberti, Ag., the best known 

 British species from the Goal Measures. 



Glyptopomus, Ag. (Glyptolaemus, Huxley), (Fig. 130). 

 Bones of cranial roof not fused together ; a median 

 frontal (pineal) foramen. External bones and scales 

 ornamented with irregulär reticulating rugae or fused 

 series of tubercles. Upper Old Red Sandstone ; Scotland, possibly also 

 Belgium and Pennsylvania. 



Fio. 130. 

 Glyptopomus kinnairdi, 

 Huxley. Scale, enlarged. 

 Upper Old Red Sandstone ; 

 Dura Den, Fifesliire (after 

 Huxley). 



