Vol. 56, pp. 73-76 June 16, 1943 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



TWO NEW COTTON RATS FROM FLORIDA 



BY ARTHUR H. HOWELL. 



These new cotton rat descriptions were found with the 

 late Arthur H. Howell's partly completed manuscript on 

 Florida mammals. — Viola S. Schantz. 



Sigmodon hispidus floridanus, new subspecies. 



FLORIDA COTTON RAT. 



Type. — Collected at Canal Point, Palm Beach County, Florida, March 

 1, 1936, by A. H. Howell; female adult, skin and skull. No. 261624, U. S. 

 National Museum (Biological Surveys collection); original number 2813. 



Range. — Greater part of central Florida (except coastal beaches), from 

 Orange Lake south to the southern side of Okeechobee Lake. 



External characters. — -Coloration of upper parts darker (more blackish) 

 than in littoralis; sides less heavily washed with buff; under parts more 

 whitish (less buffy). Compared with S. h. hispidus of northern Florida 

 and the Carolinas it is much darker and more blackish (less buffy). 



Cranial characters. — Skull similar to that of littoralis; longer and 

 relatively narrower across zygomata than that of hispidus. 



Color. — Upper parts mixed black, grayish white, and pale buff; sides 

 mixed grayish white and buff, the buff rather inconspicuous; hind feet 

 neutral gray; tail dull blackish above, slightly paler beneath; under 

 parts grayish white. 



Measurements. — Type (adult female): Total length, 302; tail verte- 

 brae, 112; hind foot, 32. Skull: Occipitonasal length, 38.1; zygomatic 

 breadth, 21; cranial breadth, 15.9; length of nasals, 15; maxillary tooth 

 row, 6.8. 



Remarks. — Cotton rats are probably the most abundant of Florida 

 mammals. They inhabit a variety of terrain but are most numerous in 

 neglected fields grown up to briers and broomsedge, or in palmetto scrub. 

 Although not as aquatic in habit as the rice rats (Orzyomys) they often 

 invade the marshes or mangrove swamps and are frequently found in 

 moist woodland. On the coast they are said to feed on mangrove shoots. 



When pineapples were grown extensively in Florida these rats proved 

 to be a serious pest. They flocked into the plantations and cut the 

 plants off near the surface in order to reach the roots, which they con- 

 sumed. They also destroyed the fruit by biting a hole in one side and 



16— Pboo. Bioi.. $90. Wash., Vol. 5§, J943. (73) 



