Fishes . forms,but with a heterocercal tail like a ganoid, imperfectly ossifiedback-bone, and other very archaic characters. The body isapparently scaleless, xinlike the true PlatysomidcB, in which the 252 The Ganoids scales are highly , also from the GermanThis species has lower finsmaiii, but may be the adultDoryptcriis is regarded bycialized offshoot from themany-rayed ventrals and thebody and fins suggest affinityDictyopygidae.—In the Dic-dtc), the body is gracefullypressed, the heterocercal tailturned upwards, the teethhooked, and the bony platesthis group two genera a
Fishes . forms,but with a heterocercal tail like a ganoid, imperfectly ossifiedback-bone, and other very archaic characters. The body isapparently scaleless, xinlike the true PlatysomidcB, in which the 252 The Ganoids scales are highly , also from the GermanThis species has lower finsmaiii, but may be the adultDoryptcriis is regarded bycialized offshoot from themany-rayed ventrals and thebody and fins suggest affinityDictyopygidae.—In the Dic-dtc), the body is gracefullypressed, the heterocercal tailturned upwards, the teethhooked, and the bony platesthis group two genera aretaining numerous species. Interns Rcdficld, not of Agassiz) A second species, Doryptcriiscopper shales, has been described,than Doryptcriis Jioff-of the same as a spe-PlatysomidcE. Thegeneral form of thewith the Lampridee,tyopygidce {Catopteri-elongate, less com-is short and abruptlyare sharp and usuallywell developed. Ofrecognized, each con-Rcdficldiiis { = Catop-the dorsal is inserted. FiQ. 187—D^.ryplerus hifjmani Gcrmiir, ristorcd. (After Iliincock and Ilowse.) behind the anal, while in Dictyopyge this is not the case. Red-fieldiiis gracilis and other species are found in the Triassic ofthe Connecticut River. Dictyopyge macrura is found in the sameregion, and Dictyopyge catoptcra and other species in Europe. The Ganoids 253 Order Chondrostei.— ^he order Chondrostei {xovdpoz, carti-lage; oareov, bone), as accepted by Woodward, is characterizedby the persistence of the notochord in greater or less degree,the endoskeleton remaining cartilaginous. In all, the axonostsand baseosts of the median fins are arranged in simple regu-lar series and the rays are more numerous than the sup-porting elements. The shoulder-girdle has a pair of infra-clavicular plates. The pelvic fins have well-developed base-osts. The branchiostegals are few or wanting. In the livingforms, and probably in all others, a matter which can neverbe ascertained, the optic nerves are not decu
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