1904.] Allen, Mammals from Tropical America. 69 



equally intense throughout. Costa Rica specimens of boruc& 

 present quite a range of variation in depth of coloration, and 

 some of the darker specimens quite closely approach chiri- 

 quensis, but the well-marked differences in the form of the 

 bullae and the width of the postpalatal opening seem constant. 



20. Oryzomys costaricensis Allen. 



Oryzomys vegetus BANGS, Bull. Mus. Comp. Zool., XXXIX, No. 2, 

 April, 1902, 35. 



Seven specimens, Boquete (topotypes of O. vegetus), Aug. 

 19-29. 



The type and 12 topotypes of 0. vegetus, kindly sent me for 

 examination by Mr. Bangs, do not differ appreciably from the 

 type, 3 topotypes, and additional Costa Rica specimens of 

 O. costaricensis. They also agree with the 7 Boquete speci- 

 mens collected by Mr. Batty, which I unhesitatingly refer to 

 O. costaricensis. 



Mr. Bangs's O. costaricensis (I. c.), of which he has kindly 

 sent me his series of 5 specimens, seems to represent merely a 

 pale phase of 0. costaricensis, due to individual variation. 

 They are paler rufous above and nearly white below, but simi- 

 lar specimens occur in my series of 15 specimens from Costa 

 Rica. The type of O. vegetus is, with one exception, the 

 highest colored specimen of Mr. Bangs's series, but it is not 

 very appreciably brighter than the type of 0. costaricensis. 

 Mr. Bangs informs me that he inadvertently placed the name 

 vegetus on the dark form (= costaricensis vera) instead of on 

 the light form, after having returned the specimens of O. 

 costaricensis borrowed from this Museum, so that vegetus = 

 costaricensis and the light form was left unnamed. As said 

 above, it does not appear to be separable from true costari- 

 censis; it is represented by 5 pale specimens selected from his 

 series (=13 'vegetus' + 5 'costaricensis'), all taken at the 

 same locality, and some of each on the same dates. 



21. Zygodontomys cherriei Allen. Eleven specimens, Bo- 

 queron, Oct. 12 and 25-31, and Nov. 20 and 25. 



