the Genera 0) Hapalidee. 249 
is any improvement upon that of Gray, who in some parti- 
culars showed his usual instinctive, if unintelligent, anticipa- 
tion of modern views in the matter of generic subdivisions, 
Trouessart’s classification was a mere list of names. 
With regard to two of the generic names I adopt in this 
paper—namely, Hapale and Mystax—the following explana- 
tion must be given. By the rules of nomenclature the 
correct name for the group of marmozets typified by jacchus 
is Callithriz, as Thomas has shown, ‘The latter title, 
however, has for many years been used for the “Titis » 
(Callicebus) of the family Cebides ; and jacchus and its allies 
in all anatomical treatises and natural histories, popular and 
scientific, are universally assigned to Hapale. Similarly, if 
Gronovius be admitted as a binominalist—a question on 
which opinions are divided,—the oldest name for the genus 
typified by midas, Linn., is Cercopithecus, a title invariably 
associated with one of the African Catarhine Primates until 
Elliot published his monograph. The confusion created by 
the adoption of Callithrix and Cercopithecus for two 
marmozets, involving, as it does, even familiar family-names, 
will be great and regettable. They have therefore been 
added to the list of generic terms recommended for exemption 
from the strict rule of priority and for permission to stand for 
the genera to which for half a century or so they have been 
affixed. Pending the decision of the “ Fiat Committee,” 
which now has these cases under consideration, I have 
adopted Hapale instead of Callithriz and the next available 
name for the genus called Cercopithecus by Elliot, in the hope 
that the verdict of the Committee will endorse these decisions. 
The Hands, Feet, and Ears of Marmozets. 
Examination of fresh material of some of the commoner 
species of marmozets has revealed one or two external 
characters surpassing in systematic value those employed by 
Gray and Hlliot for distinguishing genera. 
The Hands and Feet.—In Hapale jacchus the five digits of 
the hand are tolerably evenly spaced, and are separated | down 
to a point almost or quite on a level with the anterior border of 
the plantar pad, so that from the plantar aspect scarcely any 
- webbing is visible. ‘he pollex is tolerably long and is set 
low down a little behind the first digit, and reaches es OxI- 
mately to the distal end of its first “phalanx when the digits 
are placed together. The palm of the hand is short and wide, 
its width across we plantar pads considerably exceeding half 
its length. 
Ann, & Mag. N. Hist. Ser. 8. Vol, xx. 17 
