510 DR. P. CHALMERS MITCHELL ON LONGEVITY AND 



"Pt AmATr-TTM^ No. of Av. dur. Max. dur. 



i-LAlALLID^. jj^ijjy_ in months, in months. 



Flataleci alba {AMc{\.n ^poonhiW) 2 21 29 



P. leiocorodia (SpoonhiM) 19 16-5 115 



Jj«/a rosea (Roseate Spoonbill) 11 19 38 



Ibis, ^yhole genus 17 80 220 



/. cethiopicus (Sacred Ibis) 8 94 191 



/. Sermeri (Bernier's ,, ) 2 25 38 



/. mela7iocep]ialus (Black-headed Ibis). 1 83 83 



/. strictipennis (Australian Sacred ,, ). 6 87 220 



Carphibis spinicoUis (Straw-necked 4 109 "8 300 



Ibis). 



Nipponia temmincki (Nippon ,, ). 1 5 5 



Theristicus caudatus (Black-faced ,, ). 3 16 41 



T. melanopis (Grey ,, ). 5 18 31 



Plegadis falchiellus (Glossy ,, ). 18 30*5 112 



P. guarauna (White-faced ,, ). 2 5 5 



Eudocimus, whole genus 43 25*5 143 



E.albus (White Ibis) 5 69-5 143 



E. longirostris (Red-billed „) 2 8*5 12 



E. ruber (Scarlet „) 36 20 90 



Mr. J. H. Gurney {loc. cit. p. 38) records from our own Gardens 

 a Sacred Ibis alive at 20 years okl, and another bird of the same 

 species from Rotterdam of 11 years. In the list given above 

 there is a Straw-necked Ibis with a duration of 25 years, and an 

 Australian Sacred Ibis of over 18 years, whilst there are a number 

 of other high records. The figures of average duration are very 

 varied, but in several cases they extend to a number of years, the 

 low figures being chiefly birds of which there were veiy few 

 examples. 



In the period in question nearly all these birds had free access 

 to the open air, but in some cases had shelter in a heated aviary 

 in winter. Ibises have a simply disposed but rather long in- 

 testinal tract, with the ca3ca and the hind-gut much reduced. 

 It must be inferred from the figures that they ai-e birds of 

 good viability in proportion to their size. 



Siiminary of Herodiones. 



Herons, Storks, Spoonbills and Ibises form a cohei-ent zoolo- 

 gical group all chiefly carnivorous or piscivorous, with relatively 

 long, narrow, intestinal tracts, the posterior region of which is 

 reduced and uncapacious. Within the different groups there is 

 a fair correspondence between duration and size, but this does 

 not reach to the whole assemblage, as the Spoonbills and Ibises 

 show a better viability than the Storks, whilst the Herons are 

 lowest of all. I see no reason for assuming much difference 

 (except perhaps in proportion to size) between the potential 

 longevities of the three divisions, and must assume that the 



