

462 THE ANOMALURES 



as gnawing and excavating tools as well as for the purposes of 

 alimentation ; for it allows of substances being gnawed away 

 without the products of the chisel-like action being taken into 

 the hinder cavity of the mouth. The Rodents have for the most 

 part a simple stomach of normal form ; but in a few this is 

 complicated by a marked constriction, which divides the cardiac 

 from the pyloric portions. The Hamster, for example, is thus 

 characterised. In all the members of the order, with the excep- 

 tion of the Dormice and some allied forms, the caecum is large 

 and often sacculated. In some forms (e.g. Arvicola, Myodes, 

 Cuniculus) the large intestine is coiled upon itself in a spiral way 

 a state of affairs strongly suggestive of Ruminants. 



The Rodents are primarily divisible into two great groups, the 

 Simplicidentata and the Duplicidentata, characterised mainly by 

 the upper incisor teeth. In the former there is but one pair of 

 these teeth ; in the latter a second smaller pair lie behind the 

 former. 



' SUB-OEDEE 1. SIMPLICIDENTATA. 

 SECTION 1. SCIUEOMOEPHA. 



The Anomaluri are separated by Thomas and others from this 

 section as an equal section, while by Tullberg they are grouped 

 with Pedetes. 



Fam. 1. Anomaluridae. The genus Anomalurus suggests at 

 first sight the Flying Squirrels of Asia, Pteromys. It is, how- 

 ever, an entirely African genus, and is to be distinguished from 

 the Asiatic Rodents by a series of scales at the root of the tail, 

 imbricated, keeled, and forming possibly a " climbing organ." 

 This character serves also to distinguish the present genus from 

 Sciwropterua. The cartilage, moreover, which supports the 

 patagium springs from the elbow. There are four molars in each 

 half of each jaw. The eyes and ears are large. There are five 

 fingers and toes, but the thumb is small, though provided with 

 a nail. The sternum has seven joints, and nine ribs reach it. 

 The clavicle is strong. Huet, who has recently monographed the 

 genus, 1 allows six species. The species vary in size. 



"Observations sur le genre Anomalurus," JVouv. Arch. Mus. (2), vi. 1883, 

 ]). 277. 



