5. CERUS. 47 
C. monacuus, F. Cuv. Mamm. Lith. t. 76, p. 31. C. wanthoster- 
nus, Pr, Max. C. wanthocephala, Spix. 
** Lumbar vertebre 6. Head smail. 
C. capucinus. (Old) C. flavus, Geoff. (Var.) C. fuluus,Desm. C. 
gracilis, Spix. C. chrysopus, F. Cuy. 8S. albifrons, Humboldt. 
C. mgro-vitiatus, Natterer. 
C, orrriver, Pr. Max. C. niger, Geoff.; Buff. Supp. vii. t. 28. 
C. cristatus, F. Cuv. 
C. nyporgvcus, Geoff. ; Buffon, v. t. 9. 
There are many skulls of this genus in the Museum from very 
differently coloured specimens. The adult ones are very much 
alike in size, external form, and in dentition, offering no important 
characters by which they can be divided into groups. (See Gray, 
P. Z. 8. 1865.) 
Dr. Dahlbom arranges the specimens in the Paris Museum in 
his “ Tabula Synoptica,” p. 164, thus :— 
I, The hair of the crown erect, subfasciculate—1. C. robustus ; 
2. C. elegans; 3. C. Pucheranii=C. capucinus, Geoff.; 4. 
C. elegans, var. 5. C. frontatus; 6. C. cirrifer; 7. C. vel- 
lerosus. 
II. Hair of the crown adpressed. 
a. The beard of the cheek and throat very diffused.—8. C. bar- 
batus ; 9. C. variegatus. 
b. Beard of cheek and throat less prominent; crown defined 
with a pale edge.—10. C. flavus; 11. C. Apella. 
¢. Cheek, chin, and throat hairy.—12. C. capucinus; 13. C. 
castaneus ; 14. C. versicolor; 15. C. chrysopus. 
In the compilation of Lesson, Wagner, and Giebel, who depended 
upon the descriptions of authors, without having the opportunity of 
examining specimens to correct their theories, the species are mixed 
together in a manner that is not confirmed by reference to the 
specimens themselves, showing how dangerous it is to venture in 
such compilations to go beyond the authors consulted. 
There seems to be a considerable difference in the length of the 
toes of the stuffed specimens, and I considered it a good character ; 
but I now suspect that it may depend on age (as the younger stuffed 
specimens always appear to have longer fingers and toes than the 
older ones), and perhaps more on the art of the preserver. 
The species may also be divided thus, by the colour of the fur :— 
The greater number of specimens have the front of the fore legs 
and chest pale. 
I. Fur black or brownish-black.—C. lewogenys, C. cirrifer, C, 
vellerosus, O. leucocephalus, C. hypoleucus. 
Il. Fur yellow, or yellow-and-brown, or brown-and-yellow 
