MAMMALIA QUADHUMANA. 247 



proportion to the body, the latter being slender, and its fur intensely black. 

 These characters, which arc scarcely rcdiscoverable in stuffed specimens, 

 would not withhold me from persisting in the union of A. ater and pauiscus, 

 did not our author subjoin to them the statement that the young in the 

 former species are black at their birth, but in the latter, on the contrary, of 

 a dirty olive green tint. According to a specimen preserved in spirits of wine, 

 in wlu'ch the thumb was wanting to the right, but present on the left 

 fore-hand, I had united A. paniscus and pentadadylus into one species, a 

 proceeding the validity of which is not admitted by Tschudi, seeing that both 

 had different circuits of distribution, and that he had never met with a case 

 similar to mine ; he therefore advances the conjecture that the specimen in 

 question might have lost one thumb by an injury. Now this is certainly not 

 the case, as is proved by inspecting the right fore-hand, when the pollicial 

 deficiency is seen to have been congenital. Yet at present I would not lay 

 so much stress as heretofore upon this circumstance, since I learn from 

 Tschudi's account that both the species of Spider-Monkeys occupy Very 

 dill'rrenl kinds of range, a fact that had also been previously told to me by 

 Natterer, who met, indeed, on his travels, with A. paniscus, but never with 

 A. pentadactylus. 



Like the Reporter, Tschudi distinguishes only two species of Lftr/othrie 

 but interprets differently their synonymy. The L. cana, Geoffr., is regarded 

 by Tschudi, after a comparison with the Parisian specimen, as not identical 

 with the Gastrimargus olivaceus, Sp., but with the latter's G. infumatus. If 

 this view be correct, then both the name as well as the description given by 

 Geoffrey and Desmarest of their Z. cana is thoroughly incorrect, since Z. 

 i,//'t'itiata has an entirely different colour. In order that no confusion might 

 be caused to interrupt the definite settling of these doubts, I retain for the 

 latter species the name given it by Spix, while his Gastrimargus olivaceus is, 

 without hesitation, to be denoted as Z. Humboldtii, just as Tschudi de- 

 scribes it. 



The same traveller estabb'shes three species of Howling Monkeys, from 

 Peru ; viz. Mycetes stratniiieus, rnfimanns, and flavicaudatus. These three 

 species I had blended with the Caraya, by reason of their being collectively 

 very imperfectly known, and only through the medium of isolated indivi- 

 duals. But after learning from Natterer that he had never seen a specimen 

 in the whole of Brazil which would agree with the M. stramineus mounted in 

 our collection, I have since regarded it as the representative of a distinct 

 species. From Natterer I likewise learnt that the M. nifimanm hitherto 

 known only by one specimen, had been frequently seen by him in troops, 

 and that the female and young are not yellow like the Caraya, but coal-black 

 like the male. Hereupon I saw myself necessitated to establish M. 

 also as a species per se. Again Tschudi expresses himself in 



