The Journal of the Linnean Society of London . s a verydistinct Ursine lozenge, but it is open behind owing to thenon-junction medially of the two halves of the crucial sulcus,each hippocampal gyrus rising to the surface in a most excep- * P. Z. S. 1869, p. 482, note %. t See I. c. pi. ix. fig. 4 ; for a notice, see p. 144. \ See Proc. Zool. Soc. 1879, p. 307, figs. 1 & 2. CEEEBEAL COlSTVOLTITIOlSrS OF THE CAENIVOEA, 19 tional manoer, and forming, on eacli side, tlie boundary of themedian longitudinal fissure of the cerehrum. JJrsus.—The Bears brain has been carefally described and ad-mirably
The Journal of the Linnean Society of London . s a verydistinct Ursine lozenge, but it is open behind owing to thenon-junction medially of the two halves of the crucial sulcus,each hippocampal gyrus rising to the surface in a most excep- * P. Z. S. 1869, p. 482, note %. t See I. c. pi. ix. fig. 4 ; for a notice, see p. 144. \ See Proc. Zool. Soc. 1879, p. 307, figs. 1 & 2. CEEEBEAL COlSTVOLTITIOlSrS OF THE CAENIVOEA, 19 tional manoer, and forming, on eacli side, tlie boundary of themedian longitudinal fissure of the cerehrum. JJrsus.—The Bears brain has been carefally described and ad-mirably figured by MM. Leuret and G-ratiolet *. I have examinedthe brains of nearly all the species, including that of the Sloth-Bear {Melursus). In all, the Sylvian sulcus has its anterior limbvery much narrower than its posterior limb ; in all, the parietalgyrus is simple and single; in all, the sagittal gyrus is verycomplex, and tends to become longitudinally divided into two ;it is greatly expanded and much convoluted anteriorly. In all the. Dorsal surface of brain of TJrsus maritimus, talf natiual size. C. Crucial sulcus. P. Parietal gyrus, jpc. Precrueial sulcus. *S. Sylvian gyrus. Sa. Sagittal gyrus. Sf. Sylvian fissure. species, the Sylvian fissure is exceedingly long and very oblique ;and in aU. the hippocampal gyrus joins the sagittal gyrus, abridging convolution dividing the crucial and calloso-marginalsulci. Finally, in the Bears we find present a large and verymarked Ursine lozenge, which in them attains its maximum ofdistinctness. It may be formed in different ways, either bysecondary sulci proceeding forwards from the crucial sulcus, orby such sulci independently placed in front of it; and the con-dition may vary on the two sides of the same brain. * See I. c. p. 375, pi. vi.; and P. Gervais, I. c. p. 134, pi. viii. fig. 10 (cast),and pi. ix. fig. 9 (brain itself); also Krueg, /. c. p. 635 and pi. xxxvii.; andBurt Wilder, I. c. fig. 10. 2* 20 MR. ST. GEOEGE MIVART ON T
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectzoology, bookyear1865
