Mammals from South America. 569 



diagnosis, the next author after Geoffroy to mention the 

 species is Desmarest, who describes fairly fully what he 

 identifies as C. person Uus from specimens brought by 

 Auguste Saint-Hilaire from the coast-region between 18° 30' 

 ami 21° S. on the rivers Itabapuana and others, including 

 the Rio Doce, Espiritu Santo — therefore from quite the region 

 where Mr. Robert's series was collected. 



in spite, therefore, of Spix, Burmeister, and other authors 

 identifying the Rio Janeiro Titi with C. personatus, it seems 

 to me that Desmarest's determination, being the first, should 

 be accepted, especially as he probably had for examination 

 the type described by Geoffroy eight years before. This 

 type would seem to have disappeared by 1851, as it is not 

 mentioned in Isidore Geoffroy'.s Catalogue of that date. 



In the Espiritu Santo specimens the upper surface and 

 especially the nape, shoulders, and arms down to the wrists 

 are broadly washed with pale greyish white. From this the 

 more southern form may be distinguished as follows : — 



General characters as in true personatus, including the 

 extent of black on the face, crown, ears, hands, and feet, and 

 in this respect similarly differing from C. nigrifrons, in 

 which only a narrow frontal band is black, the crown being 

 dark grey. Whole of upper surface greyish brown, this 

 colour extending uniformly over the nape, shoulders, and 

 back. Under surface similarly brown, without any tinge of 

 reddish on the chest. Fore limbs proximally a similar 

 greyish brown, inconspicuously speckled with buffy, very 

 different from the conspicuously whitish forearms of true 

 personatus; hands and wrists black. Hind limbs similar, 

 the greyish brown extending to the ankles. Tail dull 

 reddish. 



Dimensions of the type (measured in the flesh) : — 



Head and body 380 mm.; tail 420; hind foot 100; 

 ear 30. 



Skull : greatest length 70 ; condylo-basal length 58*5 ; 

 breadth of brain-case 35 ; front of canine to back of m 3 li)*3. 



llab. Sao Paulo and Rio Janeiro Provinces. Type from 

 Piquete, X.E. Sao Paulo. Alt. 600 m. 



Type. Adult male. B.M. no. 1. 6. 6. 3. Collected 23rd 

 Jan., 1 ( J01, by Alphonse Robert. 



Rhogeessa bombyx, sp. n. 



Largest species of the genus. 



Size decidedly larger than in R. tumida, the largest species 

 of restricted lihogeessa as yet described. General characters 

 as in that species, the ears similarly reaching, when laid 

 forward, about to the tip of the nose. Colour above and 



Ann. & Mag. N. Hist. Ser. S. Vol. xii. 40 



