MAMMALS OF PENNSYLVANIA AND NEW JERSEY. 85 



house were found to be placed just above tide level near the top of the house. 

 They were globular and composed of fine grass, several being made in one 

 house. All four species, musk-rat, water-rat, meadow-mouse and shrew, as- 

 sociated in one house, how amicably I cannot say. Newly-born meadow- 

 mice were found in two houses. The water-rats did not take preferably to 

 water when exposed, but endeavored to hide among the reeds and debris. 

 Only I out of 15 observed was seen to dive and swim away. It swam swiftly, 

 like a muskrat, wholly under water. During high water they were most easily 

 caught, being loth to leave their abodes. Some were found half a mile from 

 upland on the marsh. None were found breeding. They are considered a 

 nuisance by muskrat trappers, as during ebb tide they prowl about the run- 

 ways and "leads" of the rats and frequently spring their traps, even when 

 under water. They also gnaw the bodies of the dead rats and mutilate their 

 skins. When ousted from their nests, they leap about like a rat, but do not 

 show fight as does the meadow-mouse. 



Description of species* — The series of N. J. specimens of Oryzo7nys recently 

 secured, shows that the typical northern animal is shorter and heavier built, 

 with shorter tail, ears and feet and, relatively, a much larger skull than 

 those from Georgia, the type locality of Bachman's Oryzomys palustris ory- 

 ziverus. In color, palustris is lighter and grayer, the brownish tints in oryziv- 

 erus being replaced by pale tawny. Northern North Carolina specimens are 

 almost exactly intermediate. I would class them with oryziverus, making the 

 natural geographic limit of palustris typicus, the Chesapeake Bay and Poto- 

 mac River. I am informed they are found in muskrat houses on the Mary- 

 land peninsula. The colors of this rat are almost precisely like those of the 

 Norway rat. The appearance of the tail is also similar, but the ears are less 

 hairy. In adult size it equals, sometimes exceeding, a half- grown rat. 



Measurements. — (Series of 6 old adults from N. J.) Total length, 237 

 mm.; tail vert., 108 ; hind foot, 29; ear from crown, 12. (Series of 3 from 

 Georgia, Bangs' collection) : 255-118-30-15. The skull of the largest N. J. 

 male, whose total tail and body length is 15 mm. less than that of the largest 

 male from Georgia, has a skull i mm. longer and 2 mm. broader than the 

 latter. 



Genus Neotoma Say and Ord, Journal, Academy Natural Sciences, Philada., 



1825, vol. 4, p. 345. 



Allegheny Cave Rat. Neotoma pennsylvanica Stone. 



(?) 1857. Neotoma magister Baird, Mammals of N. America, p. 498 

 (described from fossil specimens in Carlisle, Pa., caves). 



* See also Rhoads, American Naturalist, Aug., 1902, pp. 661-663. 



