the Genera oj Plapaliclse. 249 



is any improvement upon that of Graj, 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 CallUhrix, as Thomas has shown. The latter title, 

 liowever, has for many years been used for the'^Titis'" 

 {Callicehiis') 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 CercopithecuSj a title invariably 

 associated with one of the African Catarliine Primates until 

 Elliot published his monograph. The confusion created by 

 the adoption of Cailithrix 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 Comtnittee,^'' 

 which now has these cases under consideration, I have 

 adopted Hapale instead of Cailithrix 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 Elliot 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. The pollex is tolerably long and is set 

 low down a little behind the first digit, and reaches approxi- 

 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 the plantar pads considerably exceeding half 

 its length. 



Ann. & Mag. N. Hist. Ser. 8. Vd. xx. 17 



