104 SCIURUS AESTUANS. 



Sciurus aestuans Alston. 1. c. p. 668 ; Sciurus pusil- 

 lus Alston. 1. c. p. 670. Plate XLI. 

 1880. Sciurus aestuans Thomas. P. Z. S. L. p. 400. 



According to Oldfield Thomas there are now in the British 

 Museum , specimens brought from Ecuador by Buckley , 

 which form links between Sciurus aesttmns L. and Sciurus 

 griseogena Gray. . So I do not hesitate to bring them 

 under a single head. 



Alston believes Sciurus aestuans and Sciurus pusillus to be 

 quite distinct species, meanwhile Allen regarded them as 

 being the latter only the young state of the former. After 

 a careful examination of our series and considering Alston's 

 arguments, I feel sure that Allen is in the right. Mo- 

 reover Alston gives an argument in favour to our opinion 

 as he says (1. c. p. 670): »the British Museum specimens 

 (of Sciurus pusillus) agree in size with Buöon's and Des- 

 marest's descriptions and are not yet quite adult, as shown 

 by their skulls and teeth." 



According to Alston, Sciumis pusillus has two upper pre- 

 molars as he observed in two skulls, but this number 

 seems not to be constant, for, of three skulls of the sup- 

 posed Sc. pusillus in our collection , two have one and the 

 third has two upper premolars. And although two spe- 

 cimens show not the slightest difference either iu size nor 

 in coloration , the one has two and the other has one 

 upper premolar (vide infra, N"*. 7 and 11). We possess 

 also specimens from the same locality only differing in size 

 and nearly always the small form clearly shows its youth 

 by the undeveloped dentition. 



Hab. Nicaragua; Costa-Rica; Panama; New Granada; 

 Venezuela; Guiana; W. Brazil; Ecuador; Peru and Bolivia. 



Mounted specimens in the Leyden Museum ; 



1. Adult female, Brazil, 1822. — 2,3, 4 and 5. Adult 

 female and adult males, Brazil. — 6. Adult female, Peru- 

 vian Amazons, Chyavetas, Bartlett, 3 August 1806. — 7, 



Notes from tlie Leyden JVLuseuxUf "Vol. V. 



