188 CLASSIFICATION OF MAMMALIA. 



domesticated state. To begin, then, with the rasorial or 

 scratching powers of gallinaceous fowls ; these are certainly 

 the most burrowing of frugivorous birds : now the most bur- 

 rowing of frugivorous quadrupeds are certainly not the Un- 

 gulata, but the Glires. These birds are characterized by the 

 shortness of their wings and the weakness of their pectoral 

 muscles. Now if we inquire whether it is among the Glires 

 or Ungulata that we find the corresponding appendages of 

 the vertebral axis, — that is, the fore-feet most shortened, — 

 the answer will be, certainly not among the Ungulata; where, 

 on the contrary, the Giraffe has them extraordinarily length- 

 ened : but among the Glires we have the Jerboa, in this re- 

 spect almost a bird. In general, moreover, this latter order 

 is distinguished, like the Rasores, by the strength of those 

 muscles of the two posterior appendages of the vertebral axis 

 or hind-feet, that contribute to locomotion. Gregarious habits 

 distinguish the most of the Rasores ; so they do in a still 

 more extraordinary manner the Glires. Many are insecti- 

 vorous in both orders, and some are omnivorous. The muzzle 

 or facies of Glires is short and round, very like that of Ferce y 

 there being a direct relation between the two orders. The 

 facies of Rasores is also short and round, very like that of 

 Raptores (the order analogous to that of Ferce) ; and there 

 is also a direct relation between these two orders. Many 

 Rasores perch and nestle on trees ; so do many of the 

 Glires. The Rasores generally feed on hard grain, which 

 they pick up with their hooked beak, and masticate in a tri- 

 turating gizzard : the Glires feed also on hard substances, 

 which they gnaw with their strong hooked incisors, and mas- 

 ticate with their grinders. In both orders the thumb is very 

 often rudimentary. In both orders the tail varies from an 

 extraordinary length, as in the Squirrel and Pheasant, to being 



very short, as in the Hare and Partridge No orders in 



their respective classes present the tail so spread out and flat- 

 tened as the Glires and Rasores, — witness the Beaver and 

 Peacock. In both orders the sense of hearing is much de- 

 veloped. In both orders we find animals, such as Squirrels 

 and Pigeons, with their toes perfectly free ; and others, as 

 Hydromys and Phasianus, which have them united at the 

 base by a membrane. Castor is an aquatic animal, having 

 some relation to Cetacea ; Struthio is a terrestrial animal, 

 approaching to Natatores. And so on relation comes so fast 

 upon relation, that I know not how we can for a moment 

 hesitate to place the Glires opposite to the Rasores. 



" I conceive it now to be demonstrated, that, so far as re- 

 lates to the analogies existing in nature between the orders 

 of Mammalia and Aves, we ought to place them thus : 



