ATELEUS 47 



frighten it to turn its back, when it would have seized it. The monkey, 

 however, kept its face to the foe, and the eagle did not care to engage 

 with it in this position, but probably would have tired it out. Velasquez 

 fired at the eagle, and frightened it away. I think it likely, from what 

 I have seen of the habits of this monkey, that they defend themselves 

 from its attack by keeping two or three together, thus assisting each 

 other, and it is only when the eagle finds one separated from its com- 

 panions that it dares to attack it." 



Atkleus hybridus I. GeofFroy. 



Ateles ( !) hybridus I. Geofl:'., Mem. Mus. Hist Nat., Paris, XVII, 

 1829, p.'l68; W. fitudes Zool., 1832, p. 1, pi. I ; Id. Mag. Zool., 

 1832, p. 1, pi. I; Id. Cat. Primates, 1851. p. 49; Less., Spec. 

 Mamm., 1840, p. 129; Wagn., Schreb., Saugth. Suppl., I, 

 1840, p. 201; V, 1855, p. 79: Dahlb., Stud. Zool. Fam. Reg. 

 Anim. Xatur., fasc. I, 1856, pp. 171, 172: Schleg.. Mus. Pays- 

 Bas, Simias, 1876, p. 183. 



Sapajou marginatus Slack, Proc. Acad. Nat. Scien. Phil., 1862, 

 p. 512. 



Eriodes hxbridiis Relchenh., \'ollstand. Naturg. Affen, 1862, p. 57, 

 figs. 136. 137. 



HYBRID SPIDER MONKEY. 



Type locality. Valley of the Magdalena, Colombia. Type in 

 Paris Museum. 



Geogr. Distr. Valley of the Magdalena, Colombia. 



Genl. Char. Triangular white mark on forehead. 



Color. Face black, white triangular spot on the forehead, the 

 lower point reaching each eye ; top and sides of head and nape blackish 

 brown ; shoulders, arms, legs, hands and feet also blackish brown, but 

 not quite so dark as the head ; upper parts of body pale or ashy brown ; 

 under parts of body and inner side of limbs grayish white ; tail 

 blackish brown same color as outer side of limbs. 



Measurements. Skull : total length, 109 ; occipito-nasal length, 92 ; 

 Hensel, 75; zygomatic width, 65; palatal length, 51 ; breadth of brain- 

 case, 59 ; median length of nasals, 15 ; length of upper molar series, 23 : 

 length of mandible, 70; length of lower molar series, 29. Paris 

 Museum, possibly the type, as it bears the date, 1820, procured by M. 

 Plee. 



The above description was taken from an example presented to 

 the Paris Museum by M. Baron and stated to have come from 

 Colombia. Several specimens are in the collection, and it does not seem 



