. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 340 Mr. C. T. Re^an on the Placodermi. Tlie close relationship of the Coccosteidie and Asterolepidai jiad been generally recognized until they were so widely and unnecessarily separated by Cope, a proceeding which has found more support than it deserved^ and I have no hesitation in uniting the groups of which these families are represen- tative, together with the Osteostraci, in a single order of leleostomi. It has b:'en stated that the bones of the skull of the Coccosteidaj c
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 340 Mr. C. T. Re^an on the Placodermi. Tlie close relationship of the Coccosteidie and Asterolepidai jiad been generally recognized until they were so widely and unnecessarily separated by Cope, a proceeding which has found more support than it deserved^ and I have no hesitation in uniting the groups of which these families are represen- tative, together with the Osteostraci, in a single order of leleostomi. It has b:'en stated that the bones of the skull of the Coccosteidaj cannot be homologized with those of other Teleostomes ; but, as has recently been pointed out by Jjfikel *, if we take a generalized type such as Coccosteus, the. Fiy. 3.—Diag-rauis to show the arraugement of the boues of the cranial roof in Coccosteus (A) and in a typical Crossopterygian {Rhizo- dopsis) (B) (both after Traquair). , median dermo-occipital; , lateral dermal occipital; p., parietal; /., frontal; ptf., post- frontal ; , supratemporal; ^;2n., pineal; etk., ethmoid; pinx., prffimaxillary ; so., suborbital; oj)., operculum. cranial roof-bones are arranged as in a generalized Crosso- pterygian or Stegocephalian. Posteriorly we see the three large dermo-occipital plates which we so frequently meet with in the Ehizodontidag and Osteolepidse. In front of these are the paired parietals and frontals, the latter bounding the orbits laterally and partly separated medianly by a pineal f * Sitzb. Ges. naturf. Berlin, 1902, p. 103. t The pineal plate occupies the position of the pineal foramen of some Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original London, Taylor and Francis, Ltd
Size: 2064px × 1211px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookce, booksubjectbotany, booksubjectgeology, booksubjectzoology
