. The Cambridge natural history. Zoology. Fig. 283.—Palaeoniscus macropomiis. Restoration, nearly one-half nat. size. (From Traquair.) Finally, the Chondrosteidae represent a stage in a career of degeneration, the climax of which is reached by the modern Polyodontidae and Acipenseridae. Fam. 1. Palaeoniscidae.^ —Fishes with fusiform bodies, short dorsal and anal fins, and usually with a complete investment of articulating Fig. 284.—Outline restoration of tiie skull and rhombic, rarely cycloid, ganoid secondary pectoral girdle of Palaeoniscus gcales fFiff. 283). Fulcra macropomus. are, A
. The Cambridge natural history. Zoology. Fig. 283.—Palaeoniscus macropomiis. Restoration, nearly one-half nat. size. (From Traquair.) Finally, the Chondrosteidae represent a stage in a career of degeneration, the climax of which is reached by the modern Polyodontidae and Acipenseridae. Fam. 1. Palaeoniscidae.^ —Fishes with fusiform bodies, short dorsal and anal fins, and usually with a complete investment of articulating Fig. 284.—Outline restoration of tiie skull and rhombic, rarely cycloid, ganoid secondary pectoral girdle of Palaeoniscus gcales fFiff. 283). Fulcra macropomus. are, Angular ; dr. r, branchio- stegai rays; ci, clavicle (cieithrum); d, generally present at the bascs deutary ; , dermal lateral ethmoid ; /, ^f ^l-^g median finS, and CSpCci- frontal ; , mfra-clavicle ; %.op, snooper- ^ culum ; mx, maxilla ; n, nostril ; op, oper- ally along the dorsal bordcr of culum ; or, orbit ; p parietal ; , pectoral j-j^g ^^^^j^ ^ohQ. Eibs fan; , premaxilla ; ^, preoperculum ; ^^ ;, post-temporal; , supra-ciavicie; , are not known to be present. circumorbitals ; sq, squamosal: the single en n • i. j i median bone oVeriying the short rostrum ^^uU mVCStcd by a Very COm- is probably a dermal mesethmoid, and the plete series of paired dermal one intercalated between the squamosal i , . , . , -, and post-temporal a supra-temporal. The "OneS, WhlCh m number and dotted lines indicate sensory canals. (From disposition Conform to the Traquair.) i m i /t-i- normal leleostome type (lig. 284). The secondary upper jaw includes both premaxillae and large maxillae ; and, as a rule, both the dentary and splenial bones ' Traquair, Monogr. Palaeont. Soc. 1877 ; Quart. Journ. Qcol. Soo. xxxiii. 1877 ; Trans. Soy. Soc. Edinl. xxx. , p. 22 ; Ann. May. Nat. Hist. (4) xv. 1875, p. 237 ; Smith Woodward, Mem. Gcol. Surv. N. S. Wales, Palaeont. No. 4, 1890, and No. 9, Please note that these images are extracted from scanned pag
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