. A history of British mammals . ;/. frontals ; 5y. squamosal ; Same StimuiuS the pari- /. parietal ; //-. temporal ridge. (Drawn by M. A. C. gfals mOrC extCnsivelvHinton.) 1 1 r i overlap the irontals ; con-sequently the coronal suture and posterior processes of the frontalsare reduced to a narrow notch and narrow tongues respectively(Fig. 72, 2 and 2a, and dimensions a, b, and 3 of table at p. 462).The growth of the posterior portions of the muscles causes thesupra-tympanic parts of the squamosals to encroach upon theregion occupied in the young by the lateral parts of the inter-parietal ; t
. A history of British mammals . ;/. frontals ; 5y. squamosal ; Same StimuiuS the pari- /. parietal ; //-. temporal ridge. (Drawn by M. A. C. gfals mOrC extCnsivelvHinton.) 1 1 r i overlap the irontals ; con-sequently the coronal suture and posterior processes of the frontalsare reduced to a narrow notch and narrow tongues respectively(Fig. 72, 2 and 2a, and dimensions a, b, and 3 of table at p. 462).The growth of the posterior portions of the muscles causes thesupra-tympanic parts of the squamosals to encroach upon theregion occupied in the young by the lateral parts of the inter-parietal ; the latter is therefore laterally reduced, and its growthbecomes almost exclusively longitudinal ; its greater portion issituated between the temporal ridges, and it acquires in theadults of 0. orcadensis and 0. ronaids/iaicnsis a highly character-istic pentagonal outline; the lateral processes of the supra-occipital gradually increase in saliency and the supra-tympanicfossae, from which the hinder portions of the muscles arise,. Fig. -DoRSAL Views of Skulls of Microlusorcadensis. ORCADENSIS 455 are greatly enlarged (Fig. 72 and dimensions 8, 9, and 9-8 oftable at p. 462). The pleistocene M. corneri occupies a somewhat centralposition between M. sarniiis and M. orcadensis, but it is onthe whole, as might have been expected, more primitive thaneither. The incisors are straightened and protruding, thecheek-teeth of normal aita/is pattern, but light and short; theshort nasals terminate roundly behind, the diastema is long, theposterior palatal septum grooved. The zygomata are narrow,the jugals heavy with boldly convex upper borders. Thebrain-case is long and narrow, the occiput intermediate in depthbetween 0. orcadensis and 0. sandayensis, the temporal ridgesfuse into a low but sharp inter-orbital crest, the post-orbitalcrest of the squamosals is weak, though long, the inter-parietal,coronal suture and posterior frontal processes are entirelyunmodified in the adult, retaining
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmammals, bookyear1910
