532 DR. p. CHALMERS MITCHELL OX LONGEVITY AND 



PYGOPODES. 



^, No. of Av. dur. Max. diir. 



UOLYMBID^. Indiv. in months, in montlis. 



Tachyhaptes jiuviatilis (Little Grebe) 10 10-3 50 



J^climophorus major (Great ,, ) 1 9 9 



Podiceps cristatus (Crested ,, ) 3 4-3 11 



P. griseigena (Red-necked ,, ) 1 1 1 



Colymhus arcticus (Black- throated 1 1 ' 1 



Divei') 



C. glacialis (Great Northern ,, ) 2 5-5 10 



C . septenirionalis (Red-t\vro?ite(\ ,, ) 6 5 12 



Alcid^. 



Alca torda (Razorbill) 12 9 54 



Lonivia troile {Coxjiraon GuiWemot) ... 33 6 52 



[Jria gryUe (Black „ ) . . . 6 1 2 



Fratercula arctica (Puffin) 11 5 16 



In the case of this group also, I do not know of published 

 information. The records I can give are very bad ; of 86 examples 

 the average duration is under a year, and in most cases much 

 under a year, whilst the figures would have been still worse if I 

 had included a considerable number of Little Grebes, Crested 

 Grebes, Razorbills, and Puffins that failed to live a month. In 

 all these birds the intestinal tract is of moderate length, in 

 proportion to size ; even in the Divers the cfeca and hind-gut are 

 uncapacious, whilst in the others they are vestigial. I am unaware 

 of anything in the structure of these birds from which we might 

 infer a constitutional lack of viability as compared with, for 

 instance, Gulls, and the conditions under which the attempt has 

 been made to keep them are similar. I think that their lack of 

 viability in ca,ptivity must be pai^tly psychological, and to be 

 referred to the set of causes which lower the average duration 

 in captivity of most of the familiar mammals and birds of 

 Europe. 



IMPENNES. ^'";.°f .A v. dun. Max. dur. 



Indiv. m months, in months. 



Aptenodytes pennant I (King Penguin) 9 3"6 11 



Pygosceles toeniatus (Gentoo ?? ) 8 2*5 7 



Spheniscus, whole genus 29 17'5 135 



*S'. demersus (Black-footed Penguin)... 24 20 135 



^S'. hicmboldti (Humboldt's ,, )... 2 5 9 



S. magellanicus (Siick?i&^ ,, )... 3 5 8 



/i-VZT/ptes, whole genus 16 13'5 88 



E. antipodum (Yellow - crowned 2 6-5 12 



Penguin) 



B. chrysocome (Rock-hopper ,, ) 6 12 58 



E. pachyrhynchus (Wide-beaked ,, ) 5 4 8 



P. sclateri (Sclater's „ ) 3 37 88 



