SUB-CLASS V GANOIDEI 79 



border. C. granulosus, Young sp. (Fig. 140), from English and Scottish 

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



Cheirodopsis, Traquair. Lower Carboniferous ; Scotland. 



Plati/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 LoAver Carboniferous of England 

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

 Russia. 



1 Dor i/pterus, Gevraav. A scaleless fish, showing internal skeleton. Eare 

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



Family 3. Oatopteridae. Woodward. 



Trunk elongate or elongate-fusiform ; tail abbreviate heterocercal. Head bones 

 ivell developed, ganoid ; no median series of cranial roof hones ; teeth slender, conical. 

 Dorsal fin single and not much extended. Scales rhombic, ganoid. Trias. 



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

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

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

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

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



Catopterus, Redfield {Bedfieldius, Hay). As Dictyopyge, but origin of dorsal 

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



Order 4. LBPIDOSTBI. Huxley.^ 



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

 apparatus usually complete, with branchiostegal rays, and often a gular plate ; at 

 least one series of postorhitals on the cheek between 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. Sccdes 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 hand to the Palaeoniscids, they approach so closely 

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

 from the latter. 



^ Egerton, P. M. 6-'., Figures aud Descriptions of British Organic Remains (Mem. Geol. Snrv. 

 <lec. VI., VIII., IX., XIII.). — Kner, R., Die Fische der bituminosen Schiefer von Raibl in Karntben 

 ■ (Sitzungsb. k. Akad. Wiss. Wien, math.-uaturw. CI. vol. LIIL), 1866 ; and Nachtrag, ibid. vol. LV. 

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

 Xachtrag, ibid. vol. LVI. 1867. — Vetter, B., Die Fische aus dem lithographischen Schiefer in 

 Dresdener Museum (Mittheil. k. mineral. -geol. Mus. Dresden), 1881. 



