. Catalogue of the fossil fishes in the British Museum (Natural History) ... Fishes, Fossil. 192 ACTINOPTERYGII. to some extent the superior border of the orbital cavity; this in our nomenclature is evidently the squamosal (sq.). In the majority of Pycnodonts, the space between the supraoccipital, frontal, and squamosal elements is occupied on each side by a single parietal Pi^. Mesturus leedsi; diagram of bones ot cranial roof, superior aspect, from a specimen in [the collection of Alfred N. Leeds, Esq., Eyebury.—Oxford Clay; Peterborough. eth., ethmoidal plates; fr., frontal; , me
. Catalogue of the fossil fishes in the British Museum (Natural History) ... Fishes, Fossil. 192 ACTINOPTERYGII. to some extent the superior border of the orbital cavity; this in our nomenclature is evidently the squamosal (sq.). In the majority of Pycnodonts, the space between the supraoccipital, frontal, and squamosal elements is occupied on each side by a single parietal Pi^. Mesturus leedsi; diagram of bones ot cranial roof, superior aspect, from a specimen in [the collection of Alfred N. Leeds, Esq., Eyebury.—Oxford Clay; Peterborough. eth., ethmoidal plates; fr., frontal; , median ethmoidal plate; orb., orbit; sq.,squamosal; , supraoccipital; , supratemporal; opiates in parietal region. plate ; while this plate m'Mesodon, Microdon, Stemmatodus, Coelodus, Palceobcdistum, and Pycnodus exhibits a large posteriorly-directed process with digitate extremity, arising about the middle of its hinder margin and extending immediately beneath the scales of the trunk. In Mesturus leedsi, however, the parietal region is occupied by two or more irregular plates on each side (x) ; and neither in this genus nor in Gyrodus is there any posteriorly-directed process. The ethmoidal plates, as shown in Mesturus leedsi, are most remark- able (eth.). The region in advance of the frontals is covered with polygonal tesserge, which extend even over the smooth premaxillae;. 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 British Museum (Natural History). Dept. of Geology; Woodward, Arthur Smith, 1864-1944. London, Printed by order of the Trustees
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