yOS RODENTIA 



Braiu-case not excessively flatteued, its depth 

 about twice that of rostrum ; distance from 

 lachrymal to tip of postorbital process equal 

 to about one-third condylobasal length of 

 skull ; size medium or small, form squirrel- 

 like (Ground squirrels) Citellus, p. 924. 



Brain-case much flattened, its depth not con- 

 spicuously greater than that of rostrum ; 

 distance from lachrymal to tip of postorbital 

 process less than one-fourth condylobasal 

 length of skull ; size large, form badger- 

 like (Marmots) Marmola, p. 931. 



Genus SCIURUS Liuiianis. 



1758. Scinrus Linna3us, Syst. Nat. i, 10th ed., p. 63 {vulgaris, by 



tautonymy). 

 1857. Scimus Blasius, Saugethiere Deutschlands, p. 271. 

 1893. Aphrontis Schulze, Zeitschr. fiir Naturwissensch., Leipzig, lxvi, 



p. 165 (vulgaris). 



Tjijje f<peeies. — Sciuriis vuhjar/'s Liuiu«us. 



Geograpliical (listribiitiou. — Forested regions of the northern 

 hemisphere, in the Old World from Ireland to Japan and north- 

 eastern Siberia ; southern limits of distribution at present 

 uncertain owing to lack of precise definition of the genus. 



Characters. — Strictly arboreal Sciuridse, of medium size and 

 typically sciurine aspect, the tail bushy and conspicuously 

 flattened, more than half as long as head and body ; skull witla 

 deep, strongly convex brain-case and weak rostrum ; postorbital 

 processes slender, directed backward ; incisors strongly com- 

 pressed ; anterior upper premolar vestigial, usually present as a 

 practically functioidess terete spike ; crowns of molars low, those 

 of upper teeth with two moderately developed cross ridges and a 

 broad, low inner cusp (not forming a (J -shaped pattern with 

 wear), those of lower teeth distinctly basin-shaped. 



Reviarks. — In the present uncertainty regarding the classifica- 

 tion of the squirrels, it is impossible to frame a satisfactory 

 diagnosis of the genus Sciurns, or to estimate the number of 

 forms that should be referred to the group. Only the type 

 species occurs within the limits of the present work ; it is repre- 

 sented by thirteen geographical races. 



SCIURUS VULGARIS Linmeus. 



(Synonymy under subspecies.) 



Geograpliical distribntion. — Wooded portions of Europe from 

 the extreme northern limits of tree growth to the Mediterranean 

 coast, and from Ireland eastward into Asia. 



Diagnosis. — Size medium (head and body ranging in the 

 diJTerent races from 205 to 280 mm., tail from 160 to 242, hind 

 foot from 55 to 66, condylobasal length of skull from 45 to 55) ; 



