FLORIDA MUSKRAT. 



329 



Meaturementa of Keofiher AUeni, from the typical alcoholic specimen from Oeorgiana, Fla. 



CentimetcrB. 



Length of head and body 20.2 



Length of head 5.2 



Length of tail 12. 6 



Length of hind foot (without claws) 3. & 



Length of fore foot (without claws) 2. 3 



Nose to eye 2.0 



Nose to base of ear 4.5 



Height of ear 1.8 



Length of middle toe of fore foot (without claw) J> 



Length of middle toe of hind foot (without claw) 1.0 



Longest claw of fore foot 5 



Longest claw of hind foot 6 



Measurements of the skull. 



Total length 4.7 



Greatest width 2.9 



Length of nasals 1.2 



Length of tooth- row 1. 1 



Front edge of first molar to posterior margin of incisors 1.6 



Greatest width of muzzle 7 



Width of iuterorbital bridge 5 



Center of occipital crest to line of hinder margin of orbits 1.9 



Measurevients of the skeleton. 



Total length (along curves) 



Anterior margin atlas to extremity of post-zygapophysis of last sacral vertebra. 



Extremity of post-zygapophysis of last sacral vertebra to end of tail 



Length of 7 cervical vertebrae 



Length of 13 dorsal vertebrae 



Length of 6 lumbar vertebrae 



Length of 4 sacral vertebrae 



Length of 25 caudal vertebrse 



Length of scapula (glenoid fossa to superior margin) 



Length of sternum (without ensiform cartilage) 



Length of humerus 



Length of ulna 



Length of mauus 



Length of pelvis , 



Length of femur 



Length of tibia 



Length of pes 



32.8 

 12.9 

 15.2 

 L6 

 5 

 3 6 

 2.7 

 15.2 

 2.4 

 3.2 

 2.6 

 3.3 

 2.1 

 4.5 

 3.3 

 3.8 

 4.2 



Tlie characters which have been employed to separate Arvicola and 

 Fiber relate to the feet, the tail, and the posterior lower molar. They 

 may be contrasted thus : 



Arvicola. 



Tail terete. 



Hind feet not specially modified for 

 aquatic progression. 



Posterior lower molar with three cusps; 

 the re-entrant angles opposite. 



Fiber. 



Tail compressed. 



Hind feet greatly modified. 



Posterior lower molar with four or five 

 cusps; the re-entrant angles alternate. 



