RELATIVE VIABILITY IN MAMMALS AND BIRDS. 433 



Ateles, whole genus 



(Spider-monkeys.) 



A . ater 



A. geoffroyi 



A . grisescens 



A. hybridus 



A. melaiiochir 



A . 2Xiniscus 



A . rufiventris 



A . variegatus 



A . vellerosus 



Lagothrix humbolcUi 



Nyctipithecus, whole genus 



(Douroucoulis.) 



N. felinus 



N. ruf'pes 



N. trivirgatus 



iV. vociferans 



Callithrix, whole genus 



(Teetees.) 



Pithecia, whole genus 



Oiiacaria, whole genus 



Mycetes, whole genus 



The Cebidse show the same marked dispai-ity between the 

 average duration and the maximum duration, although again the 

 latter must be considerably less than the potential longevity. It 

 is interesting to notice that the Capuchins and Squirrel Monkeys 

 display a higher viability than the others. 



Hapalid^. JJo_ of 



(Marmosets.) Indiv. 



Hapcde, whole genus 232 



H. chrysoleitcos 1 



//. jacchus 134 



H. melamira 1 



II. penicillata 94 



H. pygnicea 2 



Midas, whole genus 103 



M. chrysomelas 2 



M. geoff^roii 7 



M. labiatus 1 



M. mystax 1 



M. cedijnts 25 



M. rosalia 39 



M. rvfimanus 11 



M. ursulus 17 



Amongst the numerous Marmosets dealt with in the record, a 



