148 



reduction of eight is simply an advance, pari passu, with the increase of 

 our knowledge on the subject. We trust that we have proven the posi- 

 tion we take, and that we have seen the last of nominal species, based 

 upon the endless variations of Arvicola riparius." 



Distribution and Habits. — This species is generally abundant in the Uni- 

 ted States. It is numerous in Ohio, according to Mr. Langdon, who has 

 specimens from Madisonville, Ohio, and Brookville, Indiana. 



Dr. Hoy states that near Eacine, Wisconsin, they are found in woods, 

 burrowing under stumps and trees, also in meadows. It shows no prefer- 

 ence for low lands, as does A. austerus, but inhabits both high and low 

 lands. The burrow is simple, and of slight extent. 



The animal is gregarious, half a dozen or more inhabiting the same 

 nest in corn-shocks and potato heaps. Mr. Kennicott states that the 

 present species is not as pugnacious as A. auhtermj which, probably drives 

 it off. The voice is a harsh, creaking squal; the animal is noisy in cap- 

 tivity, crying out almost continually when several are eating together, 

 or at all disturbed. 



Sub-genus Pitymys McMurtrie. 

 Arvicola sp., Auctorum. 

 = Psammonys, LeConte, 1829 (pinetorum), (not of Rueppell). 

 = Piiymys, McMurtrie, 1831 (same type). 

 = Finemys, Lesson, 1842 (same type). 



Sub-generic Characters, — " Below medium size ; body cylindrical and 

 otherwise shrew-like in closeness and glossiness of plumage ; tail very 

 short — less than the head, little more than the hind foot j ears small, 

 mostly coneealed, sparsely pilous, with flat edges, and border of meatus 

 plane in front; feet small, both 5tuberculate j.for.e claws not shorter than 

 hind claws J palms more than half as long as soles; teats only four, in- 

 guinal; skull relatively bjoader than usual; muzzle short, very blunt; 

 nasal branch of intermaxillary reaching beyond ends of nasals ; distance 

 from tips of lower incisors to apex of descending process no greater than 

 distance from same point to back of condyle ; first under molar with only 

 one external closed triangle and two internal ones ; no spur on last tri- 

 angle of second upper molar ; back upper molar with only one exterior 

 triangle and a posterior trefoil." (Coues.) 



Aevicola (Pitymyb) piketorum LeConte. 

 Pine Mousb. 



1826. Arvicola pennsylvanica, Harlan, Pn. Am., 1825, 144 (in part; the 

 description, but not the synonomy ; not of authors). 



