süB-CLAssv GANOIDEI - 79 



border. Ö. gnuiulosus, Yoimg sp. (Fig. 140), from Eiiglish and Scottish 

 Goal Measures. Other species in Lower Carboniferous, England and Scotland. 



Cheirodopsis, Traquair. Lower Carboniferous ; Scotland. 



Flati/somus, Ag. (Figs. 141, 142). Trunk deep, rhombic or discoidal. 

 Teeth small, styliform. Pectoral and pelvic fins small. Scales finely striated. 

 F. sfriatus, Ag. (Fig. 141), from Upper Permian (Marl Slate of England, 

 Kupferschiefer of Germany). Upper and Lower Garboniferous of England 

 and Scotland ; Goal Measures of North America ; Permian of Orenburg, 

 Russia. 



1 Dort/pteras, Germar. A scaleless fish, showing internal skeleton. Rare 

 in Upper Permian (Marl Slate of Durham and Kupferschiefer of Germany). 



1 Family 3. Catopteridae. Woodward. 



Trunk elougate or elongate-fasiform ; tau ahhreviate heterocercal. Head bones 

 well developed, ganoid ; m median series of cranial roof bones ; teeth slender, conical. 

 Dorsal fin Single and not much extended. Scales rJwtnbic, ganoid. Trias. 



Bictyopyge, Egerton. Teeth small. Dorsal opposite or slightly in front 



jf the anal fin. Upper lobe of tail very short ; caudal fin forked. Scales 



'thombic, smooth or with few oblique furrows. All species small. Upper 



Trias of England, Germany, Virginia, U.S.A., South Africa, and Australia. 



Also J). rhenana, Deecke, from Lower Trias (Bunter), near Basle, Switzerland. 



Catopterus, Redfield (Bedfieldius, Hay). As Dictf/opt/ge, but origin of dorsal 

 behind that of anal fin. Fulcra fine. Trias ; North America. 



Order 4. LBPIDOSTBI. Huxley.i 



Notochord persistent, or vertebrae in various degrees of ossification. Opercidar 

 apparatus usually complete, with branchiosfegal rat/s, and offen a gular plate ; at 

 least one series of postorbitals on the cheek betweeii the orbit and preoperculum. Teeth 

 pointed or conical. No infraclavicle. Unpaired, and usually also paired fins fringed 

 with fulcra ; Supports of dorsal and anal fins equal in number to the dermal rays. 

 Caudal fin hemi-heterocercal. Scales rhombic or rhomboidal, arranged in oblique 

 series, and frequently united above and below by peg-and- socket articulations. 



To the Lepidostei are referred the " bony pikes " at present distributed 

 throughout the freshwaters of North America, besides a large number of fossil 

 genera from Mesozoic formations. They are remarkably closely related to the 

 Palaeoniscidae, and in the ossification of their internal skeleton they represent 

 a higher grade of the same type. Except a single genus from Permian deposits 

 (Acentrophorus), the Lepidosteoids are confined to the Trias, Jurassic, Creta- 

 ceous, and Tertiary, both in Europe and North America. Their maximum 

 development occurs in the Jurassic period. While the Lepidosteoids are 

 closely related on the one band to the Palaeoniscids, they approach so closely 

 to the Amioids on the other, that it is impossible to separate them distinctly 

 from the latter. 



' E'jerton, P. M. </., Figures aiul Desciiptioiis of British Orgauic Reniains (Meni. Geol. Surv. 

 'lec. \'I., VIII., IX., XIII.). — Knei\ R., Die Fische der bitmiiiiiösen Schiefer von Rail>I in Kärnthen 

 (Sitzungsb. k. Akad. Wiss. Wien, math.-naturw. Cl. vol. LIII.), 1866 ; and Nachtrag, ihüf. vol. LV. 

 1867. — Die fossilen Fische der Asphaltschiefer von Seefeld in Tyrol (ibicf. vol. LIV.), 1866; and 

 Nachtrag, ibid. vol. LVI. 1867. — Vetter, ß., Die Fische ans <leni lithographischen Schiefer in 

 Dresdener Museum {Mittheil. k. niineral.-geol. Mus. Dresden), 1881. 



