44 Bulletin American Museum of Natural History. [Vol. XX, 



This specimen is gray, with a pale brownish tinge over the 

 shoulders and on the middle of the back, but wholly lacks the 

 usual gray shoulder stripe of the laniger group. It therefore 

 agrees very closely with what may be regarded as the average 

 condition of C. I. pallidus, judging from Mr. Thomas's descrip- 

 tion. The specimen is a full-grown female, and measures as 

 follows: Total length, 665 ; tail vertebrae, 405 ; hind foot, 40.5. 



2. Metachirus fuscogriseus Allen. Four skins and skulls 

 of two-thirds grown specimens, and an adult skull, from Juan 

 Vinas, March 14-16. 



3. Didelphis marsupialis etensis Allen. One skin, without 

 skull, -Pozo Azul, May 26. 



4. Mazama sartorii (Saussure). One specimen, a young 

 male, Pozo Azul, July. 



5. Sciurus (Echinosciurus) thomasi Nelson. One specimen, 

 an old male, Pozo Azul, March 14. Total length, 460; tail 

 vertebras, 230; hind foot, 59. 



6. Sciurus (Guerlinguetus) hoffmanni (Peters). Ten speci- 

 mens, all adult, collected as follows: Volcan de Irazu, 5, Feb. 

 24 and March 2-5; Rancho de R. Jimenez, 3, April 5-8; 

 Pozo Azul, 2, June 18. 



These specimens vary greatly in color, especially the ven- 

 tral surface, and are fairly separable into two series, those 

 with orange-yellow bellies and those with reddish ' orange 

 bellies, there being four of the former and six of the latter. 

 As, however, specimens of each were taken the same day at 

 the same locality, and each series includes both sexes, the 

 variation is evidently purely individual. The upper surface 

 varies correspondingly, as does the tail, in which the color 

 of the fringe varies from yellow (one specimen) to deep reddish 

 orange. 



These specimens, taken collectively as a series, do not differ 

 appreciably from a series of 14 examples from Chiriqui, 

 Panama, or from specimens from other localities in Costa 

 Rica, in which pale-bellied specimens are also more or less 

 frequent. 



