. A descriptive catalogue of the marine reptiles of the Oxford clay. Based on the Leeds Collection in the British Museum (Natural History), London ... Reptiles, Fossil. M ETRIORI-IYXCHUS. 157 being preserved. The plates unite with one another in a complex interlocking suture; they are thickest on their inner edge, which, like the outer, is irregularly serrated; the number of plates in each eye is not known. Mandible (PL XI. fig. 3 ; text-fig. 60).—The mandible in Metriorhynchus is very similar in its general structure to that of Steneosanrus, but is distinguished from it by the want of any exp
. A descriptive catalogue of the marine reptiles of the Oxford clay. Based on the Leeds Collection in the British Museum (Natural History), London ... Reptiles, Fossil. M ETRIORI-IYXCHUS. 157 being preserved. The plates unite with one another in a complex interlocking suture; they are thickest on their inner edge, which, like the outer, is irregularly serrated; the number of plates in each eye is not known. Mandible (PL XI. fig. 3 ; text-fig. 60).—The mandible in Metriorhynchus is very similar in its general structure to that of Steneosanrus, but is distinguished from it by the want of any expansion of the anterior end and by the absence of any lateral vacuity. The dentaries (d.) are very large elements. Anteriorly they unite in a symphysis [sym.) to an extent which varies in the different species; in the hinder part of the symphysis they are separated by the wedge-like anterior ends of the splenials (spl.), which are thrust between them to a varying extent. The ventral surface of the symphysis is evenly convex from side to side, and is usually more or less sculptured by numerous grooves and pits; one groove with vascular pits at intervals, runniug a little below Text-fig. 60. &9n9- Mandible oE Metriorhynchus cultridens: A, from outer fide ; B, from inner side. (R. 3804, J nat. size.) any., angular ; art., articular ; cor., coronoid ; d., dentary ; , prearticular ; , surangular ; spl., splenial; sym., symphysis. the alveolar border, is particularly well marked, especially on the hinder part of the dentary, behind which it is continued along the line of suture between the angular and surangular elements. The oral (upper) surface is smooth and slopes down to the middle line from the ridge which forms the inner border of the row of alveoli. The number and arrangement of these vary greatly in the different species. Posteriorly, as already noted, the inner face of the dentary is overlapped by the outer side of the splenial, while externally it ta
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectreptile, bookyear1910
