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



the fifth on the right antler comes off at the inner base of the basal 

 tine, and in the left is produced by the slight forking of the main 

 branch of the antler, which is not, however, homologically the main 

 beam. (Fig. 17 , g and g'.) Length of main beam, 336; circumference 

 at base, 120 (right antler) and 150 (left antler). In the left antler the 

 basal prong is situated close to the bur, in the left at the usual point 

 (about one third the length of the main beam above the bur). The 

 animal that carried these antlers was doubtless very old, as well as 

 very large, the portion of the cranium attached to the antlers being 

 very heavily ossified, giving great breadth to the frontal processes sup- 

 porting the antlers, while the diameter of the brain cavity is slightly 

 less than in the youngest specimens of the series. 



The eighth pair (No. 21571) is curiously malformed, as shown by 

 the photograph reproduced in figure 18. The left antler, the longer of 

 the pair, has a length of only 150 mm., and is abnormally developed 

 throughout, the part that may be homologized as the basal tine start- 

 ing from the bur, and being one half as long and nearly as massive 

 as the main beam. The left frontal bone at the base of the antler 

 shows exostosis and other unnatural conditions. The chief interest of 

 the specimen is pathological, although it strongly recalls the specimen 

 figured long ago by Pennant, which later became the basis of Cervus 

 mexicanus of some of the earlier systematists. 



12. Sciurus (Echinosciurus) melania (Gray). Ten speci- 

 mens, Boqueron, Sept. 4-Dec. 29; selected from a large 

 series, to show seasonal variation in color and pelage, already 

 well described by Mr. Bangs (/. c., p. 22). His specimens were 

 from Divala, Bogaba, and Boquete, from sea level to 2000 

 feet altitude. 



13. Sciurus (Echinosciurus) adolphei dorsalis (Gray). A 

 single specimen from Remedies (collected by D'Arce), of the 

 'rigidus' type. 



14. Sciurus (Guerlinguetus) hoffmanni (Peters). 



Sciurus (Guerlinguetus) csstuans chiriquensis BANGS, Bull. Mus. 

 Comp. Zool., XXXIX, No. 2, April, 1902, 22. 



Fourteen specimens: Boquete, 7, Aug. 22-Sept. 8; Bo- 

 queron, 7, Oct. Q-Nov. 25. Selected from a large series, to 

 show seasonal and individual variation. 



It appears to me that the Chiriqui animal is indistinguish- 

 able from Costa Rica specimens of true 5. hoffmanni. The 



