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VERTEBRATE ZOOLOGY 



of the beaver (Fig. 192, D) are too well known to require description 

 here. They are nearing extinction on account of their highly desirable 

 fur. No other rodent is so highly modified for aquatic life as is the 

 beaver. 



FIG. 192. Group of Rodentia. A, Flying Squirrel, Sriuroplerus volucella (after 

 Lydekker); B, Long-tailed Marmot, Aiclomys caudalus (after Beddard); C, 

 Egyptian Jerboa, Dipus jaculus (after Lydekker); D, Beaver, Castor fiber (after 

 Lydekker); E, Agouti, Dasyprocta aguti (after Beddard); F, European Por- 

 cupine, Hystrix cristata (after Beddard.) 



