GENERAL CHARACTERS OF THE QUADRUMANA. 341 



from the situations assigned them by Cuvier and others, and restore 

 them to their true and legitimate station. The animals in question are, 

 the Aye-Aye (Cheiromys Madagascariensis), and the Colugo (Gen. 

 Galeopithecus, Pallas). With respect to the Aye-Aye, though pedi- 

 manous, or with the feet having a true thumb, the fore-hands are not 

 thus organized, nor is its dental system such as generally exists in the 

 Quadrumanous order ; yet Schreber appreciated the affinities of the 

 Aye-Aye ; and though Cuvier placed it among the rodents (as did 

 Gmelin, under the title of Sciurus Madagascariensis), he, at the same 

 time, acknowledges its relationship to the Lemurs, to which family 

 Schreber referred it. 



The Colugo is neither furnished on the fore nor hind feet with 

 an opposable thumb : notwithstanding this circumstance, however, the 

 totality of its characters sufficiently vindicates its claim to a place 

 among the Lemuridse ; to which group it was referred by Linnaeus, 

 under the title of Lemur volans. It may farther be observed, that it is 

 not in the typical, but in the aberrant families of an order, that the great 

 fluctuations of characters, which pervade it as a whole, are to be looked 

 for : in every aberrant, or abnormal family, extreme links in the chain 

 are often found to depart so much from the type, that it is only by a 

 careful analysis of the whole group, that the naturalist can detect their 

 affinities, follow the gradual loss of some characters, or the rise and 

 progress of others, and, at length, confidently assign the group to its true 

 situation. The non-opposable condition of the thumb in the fore-hands 

 of the Aye- Aye, and in all the extremities of the Colugo, is an exception 

 to the general rule among the Lemuridae : not so, however, is it among 

 the Cebidse, or Monkeys of the New World, in which, as affecting the 

 fore-hands, this peculiarity becomes a standard character. 



Some naturalists of eminence object to the application of the term 

 hands, to organs which, furnished, as they may be, with flexible and 

 hand-like fingers, have the thumb incapable of antagonizing with them ; 

 and hence they deny the title Quadrumana to all the groups included 

 by Cuvier in the order thus denominated. It is true that Cuvier was 

 not aware of the universality of this fact in the Cebidse ; nevertheless, 

 he perceived it in the Ouistitis, and observes : " All their nails are com- 

 pressed, or pointed, with the exception of those on the thumbs of the 

 hinder hands ; while the thumbs of the fore-hands are separated so little 

 from the other fingers, that one hesitates to give to these animals the 

 name of Quadrumana." 



The non-opposable character of the thumb was long since observed 

 and pointed out by Azara, as a characteristic in certain species of the 

 genera Cebus, Mycetes, and Pithecia ;* but was universally overlooked 



* Azara, Quad, du Parag., torn. ii. pp. 213. 233. 214. 



