RICE RATS 277 



ORYZOMYS NATATOR Chapman. 



Oryzomys palustris ftatator Chapman, Bull. Am. Mus. Nat. Hist., Vol. v, 

 pp. 44-46, March 17, 1893. 



Type from Gainesville, Florida. 



Characters. — Size very large ; ears short ; tail long ; pelage long 

 and full ; color fulvous brown with an extensive dark dorsal patch ; 

 underparts white ; skull large, long and massive ; general appearance 

 of upperparts suggesting the muskrat. 



Color. — General color of upperparts grayish bister, becoming buffy 

 gray on sides, and buffy fulvous on rump and posterior back ; head 

 and back darkened by copious admixture of long brownish black hairs 

 which are so profusely abundant as to form a broad, ill-defined patch 

 covering the greater part of back and rump ; underparts white, the 

 slaty underfur showing through ; tail brownish black above, soiled 

 whitish below. 



Cranial characters. — Skull large and massive, elongate, flattened 

 on top, with strongly projecting everted superciliary ridges, which 

 greatly increase the breadth across the orbits posteriorly ; zygomata 

 moderately spreading ; palatal slits large and open. Compared with 

 palustris the skull is much larger and heavier, with broadly expanded 

 supraorbital ridges and much larger and more broadly open incisive 

 foramina. 



Measurements. — Average of 6 males from Lake Kissimmee, Fla. : 

 total length 295 mm. ; tail vertebrae 151 ; hind foot 35. 



Remarks. — Specimens from Cape Canaveral agree in color with 

 natator but are decidedly smaller. Their skulls are intermediate be- 

 tween those of natator and palustris. 



ORYZOMYS NATATOR FLORIDANUS subsp. nov. 



Type. — From Everglade, Monroe County, Florida. No. 71349, $ 

 ad. U. S. National Museum, Biological Survey Coll. March 29, 

 1895. J. Alden Loring. Original number 2819. 



Characters. — Similar to natator but much smaller, with cheeks 

 and sides more inclining to fulvous; skull decidedly shorter, with 

 more broadly spreading zygomata (outer sides nearly parallel) . 



Measurements. — Average of 6 males from type locality: total 

 length 367 mm. ; tail vertebrae 137; hind foot 33. 



ORYZOMYS AQUATICUS Allen. 

 cus Allen, Bull. Am. Mus. 



Type locality. — Brownsville, Texas. 



Oryzomys aquaticus Allen, Bull. Am. Mus. Nat. Hist., New York, iii, 289, 

 June, 1 89 1. 



