OCR Text |
Show 1876.] MR. E. R. ALSTON ON THE ORDER GLIRES. 61 attached. The intestines are particularly capacious, being quite inch in diameter ; they are four feet in length, and have no colic caeca connected with them. The liver has a gall-bladder ; and the left of the two lobes which go to form it is a little the smaller. In the syrinx there is a pair of intrinsic muscles to the first bronchial half-ring. The tongue is almost as small as it is in the Pelicans. Myologically, of the five muscles in the thigh, which, in m y estimation, are specially significant*, the ambiens is absent, as are the femoro-caudal and the accessory femoro-caudal, the semitendinosus and the accessory semitendinosus being well represented. In this respect Bucorvus, therefore, differs from Buceros and Toccus, the accessory femoro-caudal muscle being present in the two latter genera. As is most probably known to many, Bucorvus walks, placing one foot in front of the other, whilst Buceros always hops, with both feet together. 2. O n the Classification of the Order Glires. By E D W A R D R. ALSTON, F.G.S., F.Z.S. [Received December 14, 1875.] (Plate IV.) The following attempt at a natural arrangement of the gnawing mammals is the result of a revision of the genera of that order, undertaken at the suggestion of Professor Flower, on which I have been for some time engaged. In laying it before the Society it may be well to say at once that the proposed classification has few claims to novelty, being in fact a modification of that first suggested by Mr. Waterhouse, and since improved by Professors Gervais, Brandt, and Lilljeborg. Nevertheless I have found it necessary to propose several changes in the arrangement of the families and subfamilies, as well as rectifications in their nomenclature. I have also taken the fossil forms into consideration, and have thereby been compelled to propose the establishment of a new suborder. Lastly, I have endeavoured to bring the whole up to a level with the improved state of our knowledge, which has gained much of late years from the labours of Milne-Edwards, Gray, Gunther, Leidy, Coues, and others, but, above all, from those of Dr. Peters. The order Glires has always been a stumbling-block to naturalists, owing to the immense number and variety of the forms which it includes, and to their puzzling cross-relationships to one another. Nor has palaeontology here yielded, save in a few instances, the same help which she has lent the student of some other orders of mammals ; for most of the fossil rodents yet discovered are referable to families which still exist, and are often closely allied to recent genera. * P. Z. S. 1873, p. 626, and 1874, p. 111. |