80 



PISCES 



Family 1. Sty lodontidae. Wagner.^ 



Jaws and vomer tvith several rows of teeth, those of the outer row styliform. 

 Vertebral column consisting of hemi-vertebrae or ring-vertehrae. All fins fringed with 

 fulcra. Caudal fin both internally and externally hemi-heterocercal, the upper lohe 

 more extensively scaled than the lower lobe. Upper Permian to Upper Jurassic. 



Acentrophorus, Traq. Trunk fusiform. Dorsal fin short, opposite the 

 space between the pelvic and anal fins. No enlarged ridge scales. A. varians, 

 Kirkby sp., and other species from Magnesian Limestone, Durham. A. 

 chicopensis, Newb. Trias ; Connecticut Valley, U.S.A. 



Semionotus, Ag. (Ischypterus, Egert.). Trunk fusiform. Dorsal fin large 

 and extended, its hinder part opjDosed to the anal fin. Dorsal series of pointed 



ridge scales forming a pro- 

 minent crest. Fin fulcra 

 sometimes very large. Scales 

 and head -bones smooth or 

 but feebly ornamented. /S*. 

 bergeri, Ag., from Keuper of 

 Coburg and Thuringia. S, 

 kapfii, Fraas (Fig. 143), from 

 Keuper, Haslach, near 

 Stuttgart. Other species from 

 the Bunter, Muschelkalk, 

 Keuper, and Rhaetic of Europe, also from the Upper Karoo Formation of 

 South Africa, the Hawkesbury Formation of New South Wales, and Trias of 

 Connecticut Valley and New Jersey, U.S.A. 



Semionotus iMpffi, Fraas. Keuper (Stubensanclstein) ; Stuttgart. 

 2/3 iiat. size (after O. Fraas). 







Ak 



Fig. 144. 



Dapediits phoUdotiis, Ag. Upper Lias ; Boll, Wiii'teni berg, i/.j nat. size. 

 B, C, Teeth, nat, size (after Quenstedt). 



'^Crenilepis, Dames. Muschelkalk. Homoeolepis,Vi' aguer. Upper Lias; Boll. 

 Dapedius, de la Beche (Amblyurus, Ag. ; Aechmodus, Egerton), (Figs. 144, 



^ Striiver, J., Fossile Fische aus deni Keupersandsteiu von Cobiirg (Zeitsclir. deiitsch. geol. Ges. 

 vol. XVI.), 1864. — Wagner, A., Die Grift'elzalnier (Stylodontes), (Gelehrt. Anzeig. k. bay. Akad. 

 vol. L.), 1860. — Deecke, W., Ueber Fisclie aiis verschiedeueu Horizouteu der Trias (Palaeoiitogr. vol. 

 XXXV.), 1888. — Newberry, J. S., Fossil Fishes and Fossil Plants of the Triassic Rocks (Mouogr. 

 U.S. Geol. Surv. vol. XIV.), ISSS. —Schellwien, E., Ueber Semionotus Agassiz (Schrifteu Phys.- 

 iikon. Gesellsch. Konigsberg), 1901. 



