18 



NORTH AMERICAN FAUNA 66 



Distinguishing characteristics. — This subspecies is very similar to 

 S, c. cinereus and differs from it only in minor details which are most 

 evident on the skull. Externally, the only apparent differences are 

 somewhat smaller size and shorter tail. The skull is smaller, with a 

 narrower braincase and a shorter, relatively wider rostrum. The uni- 

 cuspid toothrow is shorter than in S. c. cinereiis^ and the teeth in the 

 unicuspid row are more crowded. 



This subspecies of masked shrew closely resembles the southeastern 

 shrew {Sorex l&rigirostris) , which in the eastern United States reaches 

 the northern limits of its range in Maryland. Differences between the 

 two are discussed under the species account for Sorex longirostris. 



Measurements. — External measurements of eight adults from the 

 vicinity of Eockville, Montgomery County, are as follows : Total length 

 81.7 (76-89); tail vertebrae 33.7 (30-35); hind foot 10.6 (10-11). 

 Cranial measurements of five adults from the vicinity of Eockville 

 are: Condylobasal length 14.9 (14.7-15.2) ; cranial breadth 7.0 (6.7- 

 7.1) ; least interorbital breadth 2.7 (2.6-2.8) ; maxillary breadth 4.1 

 (4.0-4.2) ; crown length of upper toothrow (exclusive of first incisors) 

 5.5 (5.3-5.7). 



Hahitat and habits. — Bures (1948, p. 62) collected 14 masked shrews 

 (which he incorrectly believed to be Sorex longirostris) near Lake 

 Roland, Baltimore County. He says that, with two exceptions, all of 

 these shrews were taken in a mixed deciduous woods bordering a rail- 

 road siding. Of the two exceptions, one was trapped in a dense tangle 

 of sumac and honeysuckle bordering a marsh, and the other in similar 

 habitat along a small stream paralleling Falls Road. He states that 

 systematic trapping throughout the area confirmed his opinion that this 

 shrew does not wander far from deciduous woods. Hampe (1939, p. 5) , 

 however, trapped this shrew in the Patapsco State Park in the marshy 

 pastures near Glenartney, and the type specimen of the subspecies 

 was collected in a cold spring swamp in Prince Georges County. 



This shrew apparently does not occur on the outer barrier beaches 

 of the Atlantic Coast. Many weeks of trapping there failed to produce 

 a single specimen. It does inhabit the adjacent mainland, and the skull 

 of one was found in an owl pellet on Mills Island in Chincoteague Bay, 

 Worcester County. The shrew had undoubtedly been captured by the 

 owl on the nearby mainland. 



Regarding the nesting habits and young of this species, Hampe 

 (1936) writes that he examined the nest of one which was under a 

 discarded trash-filled box among the leaves about 6 feet from the road 

 between Glenartney and Vineyard, Baltimore County. It was com- 

 posed of a small bundle of dried and broken leaves loosely packed in 

 a small depression in the ground. It was fairly dry, but the surround- 

 ing ground was very damp. This nest was found on 18 October 1936 



