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Show 56 ZOOLOGY OF TilE VOYAGE OF THE BEAGLE. Inches. Lines. Trans,·crse dia.mcter of last lumbar vertebra Ditto do. of body of ditto Vertical diameter of ditto Entire length of lumbar region of vertebral column Vertical diameter of glenoid cavity of scapula Transverse ditto ditto ditto Elevation of spine of scapula . · · · · V crtical diameter of proximal articular smfaoo of foro-arm TransYerso ditto ditto ditto Height of olecranon Greatest diameter of its base . · · · · · Circumference of proximal end of anchylosed radius and ulna Entire length of inner toe of fore-foot, inclusive of metacarpal bone Breadth of proximal end of metacarpus Do. distal end of ditto Length of inner metacarpal bone Do. middle ditto Do. outer ditto Do. inner proximal phalanx Do. middle ditto Do. outer ditto Do. inner middle phalanx Do. middle ditto Do. inner distal phalanx* Do. the femur Diameter of base of articular surface of the head of ditto Greatest diameter of proximal end Do. of distal end Circumference of middle of shaft Length of tibia. Greatest diameter of proximal end Do. of distal end, including fibula Circumference of middle of shaft Length of metatarsal bone 1" "" The relative breadth of these bones is shown in the figures of the fore-foot, Pl. XI. 2 2 3 20 3 2 10 3 5 3 3 5 3 2 11 10 13 3 8 5 4 7 6 8 7 3 6 2 10 3 1· 2 2 3 1 24 3 G 7 6 3 8 18 5 7 4 4 9 7 4 t The figures in Pl. XIV. preclude tho necessity of giving tho admeasurements of the astragalus. ERRATA.-The reader is requested to substitute the word ' 1·ight' for ' left ' in the last line of p. 35, before the words 'radius,' 'fore-foot,' and ' femur,' and in the first line of p, 36, before the words ' tibia,' and ' hind-foot.' FOSSIL MAMMALIA. 57 DESCRIPTION OF A FRAGMENT OF A CRANIUM OF AN EXTINCT MAMMAL, INDICATIVE OF A NEW GENUS OF EDENTATA, AND FOR WIIICII IS PROPOSED THE NAME OF G L 0 S S 0 T H E R I U M. " LA premiere chose a faire dans l'etude d'un animal fossile, est de reconnaitre la forme de ses dents mol aires; on determine par-la s'il est carnivore ou herbivore ; " says Cuvier, at the commencement of that series of splendid chapters in which the restoration of the extinct Pachyderms of the Paris Basin is recorded. In the present case, however, as in that of the Mammiferous animal whose fossil remains we were last considering, the important organs, to which Cuvier directs our first attention, are wanting. Nor are there here, as in the Macrauchenia, any remains of the locomotive extremities to compensate for the deficiency of teeth, and guide us into the right track of investigation and comparison. The animal, the nature and affinities of which are the subject of the following pages, is, in fact, represented in Mr. Darwin's collection, by nothing more than a fragment of the cranium. This fragment, which was found in the bed of the same river, (see p. 16,) in Banda Oriental, with the cranium of the Toxodon, includes the parietes of the left side of the cerebral cavity, the corresponding nervous and vascular foramina, the left occipital condyle, a portion of the left zygomatic process, and, fortunately also, the left articular surface for the lower jaw. The importance of this surface in the determination of the affinities of a fossil animal has been duly appreciated, since the relations of the motions of the lower jaw to the kind of life of each animal were pointed out by Cuvier; but yet we should be deceived were we to establish, in conformity with the generalization enunciated by Cuvier,* our conclusion, from this surface, of the nature of the food of the extinct species under con- * "Commo le genre de vic de chaquo animal est toujours en rapport avec los mouvements dont sa machoire est susceptible, on rctronve d<\ns la conformation des surfaces dcstinecs a !'articulation, lcs particularites qui scmblcnt le determiner d'avance. Ainsi dans los animaux qui vivent de chairs, substances filmncntcuscs qui nc pcuvcnt ~tro ecrasees, mais sculcment coupecs ct dechireos, lo mouvement de ]a maohoirc iuferieurc no pcut s'cxecutcr que de haut en bas. Dans les herbivores, les frugivorcs ct lcs granivorcs, commo lo principal mouvement est celui do broiomcnt pour ecrasor, comprimor lcs herbcs ot lcs fruits, pour brisor lcs grains ct lcs reduirc, en pate, lc mouvemcnt des machoircs so fhit encore do droito a gauche, ot reciproqucment, on on memo temps, de devant en arricre, en un mot, dans un plan horizontal autant quo dans un vertical: les uns representant des ciscaux, los autrcs des meulcs de monlin." |