18/6.] MR. E. R. ALSTON ON THE ORDER GLIRES. 01 



attached. The intestines are particularly capacious, being quite an 

 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 my esti- 

 mation, 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 alwavs hops, 

 with both feet together. 



2. On the Classification of the Order Glires. 

 By Edward 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. Neverthe- 

 less 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 fcrms into consi- 

 deration, and have thereby been compelled to propose the establish- 

 ment T)f 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 mam- 

 mals ; 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. 187-3, p. 626, and 1874. p. 111. 



