56 Rev. L. Jenyns on the Distinctive Characters 



Dime7isio}is. 



Length of the head and body, from the nose 



to the root of the tail 1 6 



• of the head ........ 7 



of the tail 1 2 



of the auricle 1 



Breadth of the auricle ....... 5 



Length of the tragus . o^- 



Breadth of the tragus ........ 2 



Length of the arm 7t 



of the forearm ....... 1 2 



of the thumb 3 



of the phalanges of the middle finger, 



or the distance from the carpus to the 



apex of the wing ....... I 8 



of the thigh . 5i 



of the shank 5^ 



Exsertion of the tail beyond the inferfemoi;al 



membrane 1 



Expansion of the flying membrane ... 6 6 



I shall now detail more in particular some of the leading dis- 

 crepancies between these two species, most of which are drawn 

 from a comparative view of their respective dimensions as exhi- 

 bited in the foregoing tables. It will be observed, in the first 

 place, that in the Plecotus auritus the auricle is much larger in 

 proportion to the body, and longer in proportion to the tragus, 

 than in the P. brevimaniis : and again, that in the former species 

 the tail exceeds the forearm in length by three lines ; whilst in 

 the latter these parts are equal. There is nearly as great a 

 difference with respect to the relative proportions of the femur 

 and tibia, which are likewise of equal length in the P. brevi- 



mamis. 



