MURIDiE— SIGMODONTES— OCnRTODON LONGICAUDA. 127 



Habitat. — California {Samuels, Slimpson, Xantus). ? Guatemala (Tomes). 



"Size small. Tail considerably longer than the head and body (which 

 measure from 2.10 to 2.30 inches), usually from 3 to 8 tenths of an inch 

 longer. Hind foot .05 to .70 of an inch. Above, dark brown : beneath, 

 white, tinged with reddish yellow. A broad wash of bright fulvous on the 

 sides and cheeks." — (Baird, I. c.) 



This animal, accurately indicated by Baifd as above, is certainly dis- 

 tinguishable from O. humilis, though the full question of its specific difference 

 from humilis is perplexing. "While we have never seen an Atlantic Ochetodon 

 with the tail even as long as the body, and while even in the Middle Region 

 the tail never exceeds the trunk, there is no example of longicauda in which 

 this member is not notably longer. The trunk ranges, as shown by the fol- 

 lowing table (mostly copied from Baird's published 0113), from 1.83 to 2.40, 

 settling near 2.25 as an average, while the tail ranges from 2.25 to 3.15, only 

 once, however, touching this last figure, and usually falling under 3.00. The 

 feet, likewise, are somewhat larger, ranging from 0.G0 to 0.70, with an aver- 

 age of 0.G6, only once reaching 0.70, and perfectly connected with those 

 of humilis by intermediate measurements ; though in humilis the feet rarely 

 reach 0.G6, and will not average over 0.60. The colors of longicauda are 

 likewise noticeably different; only a restricted dorsal area is as dark as in 

 ordinary humilis, while the whole sides of the head and body are broadly and 

 brightly fulvous, and the under parts are washed with the same. This lively 

 shade is not even approximately attained in any specimen we have seen 

 except 9339 from Iowa. 



We have, therefore, little besitation in indorsing the name, though certain 

 facts arouse our suspicion and prevent us from making out a perfectly satis- 

 factory case. Thus, Audubon and Bachman have described a Carolina animal 

 nearly identical with longicauda in proportions. Then, again, in our speci- 

 mens from intermediate localities, as Missouri, Iowa, and Nebraska, the tail 

 lengthens to an equality with the body, and the feet average over 0.G0. The 

 question is resumed and more fully stated under head of the next species, 

 mexicanus. We cite the above Guatemalan reference with a query, suspect- 

 ing that this particular form does not occur in that locality ; but, of course, 

 we have no assurance that such is not the case. 



