116 



NORTH AMERICAN, FAUNA 66 



Measurements, — External measurements of five adults, and cranial 

 measurements of six adults from Laurel, Prince Georges County, are 

 as follows : Total length 127.4 (120-135) ; tail 21.2 (18-23) ; hind foot 

 19 (18-20); greatest length of skull 24.7 (24.3-24.9); zygomatic 

 breadth 17.0 (16.5-17.5) ; interorbital constriction 2.9 (2.7-3.1) ; length 

 of maxillary toothrow 7.5 (7.4-7.8) . 



Habitat and habits. — This species has a preference for sphagnum 

 bogs, and this is where most Maryland specimens have been collected. 

 It is sometimes found, however, in woodland habitats, including 

 beach-maple, oak-hickory, and pine. Specimens have even been taken 

 in grassy areas, orchards, weedy fields, and marshes, and in shocked 

 corn. 



According to Conner (1959, p. 171) the chief requirement of Synap- 

 tomys seems to be the presence of green succulent monocotyledonous 

 plants, primarily sedges and grasses, which are its main source of 

 food. 



This species may breed throughout the year, although Conner (p. 

 203) found that in southern New Jersey there was a spring peak in 

 the breeding cycle, with some breeding continuing through summer 

 and autumn. Poole (1943, p. 103) found a lactating female in Wor- 

 cester County, Md., in late November. Conner (p. 202) found that 

 litters of from two to five were usual for the species, although a 

 single embryo is not uncommon, and as many as seven young have 

 been reported. His data suggest that in the spring and summer females 

 produce a litter every 67 days. 



Wherever the southern bog lemming occurs, it is found in com- 

 pany with other small mammals such as red-backed mice, deer mice, 

 shrews, and moles, and it often occupies the same burrows as these 

 others. The nests are constructed of shredded grasses and sedges 

 and are often concealed some distance beneath the ground. Less often, 

 they are placed directly on the ground where there is sufficient ground 

 cover. Conner (p. 227) found that most of the nests in southern New 

 Jersey were located just under the surface, concealed in either hemlock 

 or moss or in other elevated mounds in the bogs. Most of the nests 

 were balls of dry shredded leaves of sedge, and had two entrances. 

 The diameters ranged from 3% to 6 inches, and the hollow spaces 

 within the nests averaged about 21/^ inches. 



Specimens examined. — Allegany County: Oldtown, 9 miles E, 1. 

 Prince Georges County: Beltsville, 1; Beltsville, 2% miles W 

 (sphagnum bog), 5; Hyattsville, 8. District of Columbia: 1. 



Other records and reports. — Montgorrhery County : Sandy Springs 

 [skull removed from stomach of red-tailed hawk] (Bailey, 1923, p. 

 118) . Worcester County: Snow HiU, 6 miles SW (Poole, 1943, p. 103) . 



