256 Mr. R. I. Pocock on 
Genus C&pIPoMIDAS, Reich. 
CEdipus, Lesson, Spec. Mamm. p. 184 (1840) (nom. preocc.); type 
titi, Less. =@dipus, Linn. 
Gidipomidas, Reichenbach, Vollst. Nat. Affen. p. 5 (1862); type edzpus. 
Hapanella, Gray, Cat. Primates, p. 65 (1870); type geoffroyz, Puch. 
On the available evidence I provisionally regard this genus 
as a specialized offshoot of the bald-faced or so-called Sento- 
cebus group of Mystax, differing therefrom in the modification 
and reduction in size of the ears—a character perhaps corre- 
lated with the nakedness of the adjoining area of the head. 
To the two above-quoted species, everywhere admitted, 
Elliot added a third—(. salaquiensis, which is possibly at 
most only a subspecies of G4. geoffroyt (‘A Review of the 
Primates,’ iii., Appendix, p. 255, 1912). 
Genus Mysrax, Gray. 
Cercopithecus, Gronov. Zoophyl. p. 5 (1763); type mzdas, Linn, (se- 
lected by Elliot). 
Midas, Geoffroy, Ann. Mus. Nat. Hist. Paris, xix. p. 120 (1812) (nom. 
preoce.) ; type rujimanus=midas. 
Mystax, Gray, Cat. Monkeys etc., 1870, p. 66; type mystar, Spix. 
Tamarin, Gray, op. cit. p. 68; type ursudus, Humb. 
Seniocebus, Gray, op. cit. p. 68; type bicolor, Spix. 
Tamarinus, Trouess. Cat. Mamm., Suppl. p. 29 (1899); type mystax 
(now selected). 
Mystaz may be regarded as a generalized type of Hapalidee, 
with normal hands, ears, and dentition. Leontocebus has 
departed from it by the scansorial specialization of the hands, 
Gidipomidas by the degeneration of the ears, and Hapale by 
the specialization of the anterior teeth of the mandible. 
Elliot gave full generic status to Seniocebus, which contains 
two species *—bicolor, Spix, and martinsi, ‘’homas,—basing 
the genus upon the nakedness of the forehead and cheeks as 
far back as the ears. But this character, merely a mark of 
maturity, clearly has not the systematic value of those 
employed in this paper for distinguishing Leontocebus, Gidipo- 
midas, and Hapale. It is equivalent rather to the characters 
used by Gray, and derived trom the hairiness of the aural 
area, for splitting up MHapale into several genera, which 
neither Elliot nor his immediate predecessors adopted. 
Moreover, adult examples of Mystaw leucopus, Giintr., a 
species which, as I have stated above, Elliot quite wrongly 
referred to the genus Hapale—or Callithriz, as he called it,— 
have the head covered with short hair back to the ears, and, 
* As stated above, S. metzeulosus, Elliot, is synonymous with Gdipo- 
midas cedipus. 
