537 



KEY TO THE EUROPEAN SPECIES OP SICISTA. 



Least depth of rostrum behind iucisors about equal to 



breadth of rostrum in same region ; crown area of m^ 



about four times that of premolar ; sides distinctly 



more yellow than back, with rather noticeable 



line of demarcation (Roumania) S. lorigcr, p. 537. 



Least depth of rostrum behind incisors decidedly greater 



than breadth of rostrum in same region ; crown 



area of m^ about three times that of premolar ; sides 



essentially concolor with back (Hungary, Denmark, 



south-eastern Norway) .S'. irt^ona, p. 539. 



SICISTA LORIGER Nathusius. 



1840. Sminthus loriger Nathusius in Nordmann, Demidoff's Voyage dans 



la Russie M6ridionale, iii, p. 49 (Odessa). 

 1840. Sminthus nordmanni Keyserling and Blasius, Wirbelth. Europas., 



p. 38 (Crimea). 



Tyjjc localitij. — Odessa, Russia. 



Geoiirapliical distribution. — South-westevn Russia, eastern 

 Roumania, Bulgaria ; limits of i-ange not known. 



Diagnosis. — Least depth of rostrum behind incisors about 

 equal to width of rostrum in same region ; crown ai^ea of m^ 

 at least four times that of premolar ; sides distinctly more yellow 

 than back, with rather well-defined line of demarcation. 



External characters. — General appearance essentially as in 

 Mus muscnliis, ])ut size less (about as in 3Ius sjjicilegus), and body 

 more slender ; tail slightly longer than head and body, obscurely 

 four-sided, the fine hairs not concealing annulations (of which 

 there are about twenty to the centimeter at middle of tail) and 

 not forming any decided pencil at tip ; ear moderately large, 

 extending a little beyond eye when laid forward, its outline 

 simple, ovate, its posterior border with large thickened lobe at 

 base, capable of completely closing the meatus, its anterior 

 border with minute though evident sub-basal notch and projec- 

 tion ; both surfaces of ear densely clothed with short hairs ; 

 basal lobe conspicuously tufted ; anterior border of nostril 

 thickened, a small wart beneath it ; space between nostrils 

 narrow, crossed by a well developed vertical ridge ; upper lip not 

 grooved in front ; feet more slender than in Mus iimsculus and 

 its allies, the fingers and toes longer relatively to palm and sole ; 

 front foot with thumb reduced to a mere tubercle to support the 

 short but evident blunt Jiail ; third digit longest, fourth slightly 

 shorter, second extending to middle of third, fifth just beyond 

 middle of fourth, pads as in Mus inusciilas ; hind foot with 

 relative lengths of digits as in Mus musculus, the second, third 

 and fourth sub-equal and longest, fifth extending nearly to 

 middle of fourth, first not quite to base of second ; claws 

 essentially like those of front feet ; sole naked, the pads 

 arranged as in Mus musculus ; postero-internal tubercle extended 



