CALLITHRIX 231 



part of back, shoulders, arms, hands and under parts, soiled white ; rest 

 of upper parts blackish brown, the hairs being white with blackish 

 brown tips, and the white shows in spots giving the back and rump a 

 mottled appearance; hind limbs and feet blackish brown; tail, black 

 and gray mixed, the hairs being gray ringed with black. Ex type 

 Paris Museum. 



Measurements. Size about as C. jacchus. Skull in mounted type 

 specimen. 



It is most likely the fact that the bare head and throat of the type 

 is caused by the hairs having slipped, as scattered ones still are to be 

 seen, rather than that these naked parts are natural. The scattered 

 colored places on the head, and the whiteness of the hairs on the upper 

 part of the body, and the white mottling of the back and rump would 

 seem to be more a condition of partial albinism of C. jacchus than 

 characters indicating a distinct species. However, it is impossible to 

 establish this as a fact, and until more proofs are obtained in other 

 specimens, duplicating the type, or examples of C. jacchus in various 

 albinistic stages, the present specimen will have to remain under the 

 name given to it by Geoffroy. 



Bates (1. c.) gives the following account of this species as observed 

 by him at Santarem: "I saw in the woods on one occasion, a small 

 flock of monkeys, and once had an opportunity of watching the move- 

 ments of a sloth. The monkeys belonged to a very pretty and rare 

 species, a kind of Marmoset, I think the Hapale humeralifer de- 

 scribed by Geoffroy St. Hilaire. I did not succeed in obtaining a 

 specimen, but saw a living example afterwards in the possession of a 

 shop keeper at Santarem. It seems to occur nowhere else except in the 

 dry woods bordering the campos in the interior parts of Brazil. 

 Altogether I thought it the prettiest species of its family I had yet 

 seen. One would mistake it at first sight for a kitten, from its small 

 size, varied colors and the softness of its fur. It was a most timid 

 creature, screaming and biting when any one attempted to handle it ; it 

 became familiar, however, with the people of the house a few days after 

 it came into their possession. When hungry or uneasy it uttered a 

 weak querulous cry, a shrill note, which was sometimes prolonged so as 

 to resemble the stridulation of a grasshopper." 



Callitheix albicollis (Spix). 



Jacchus albicollis Spix, Sim. et Vespert. Bras., 1823, p. 33, pi. 

 XXV; Fisch., Syn. Mamm., 1829, p. 60; Addend., 1830, p. 60; 

 Reichenb., Vollstand. Naturg. Affen, 1862, p. 4. 



