RELATIVE VIABILITY IN MAMMALS AXI) UTUDS. 509 



durations show a rougli correspondence witli size ; but tlie 

 relations of average to maximum duration show rather a low 

 viability for these birds. The intestinal tract is of the fish-eating 

 type, relatively very largo and of small calibre, but with vestigial 

 ca?ca and with a reduced hind-gut. The conditions under which 

 these birds have been kept differ ; some were placed in open 

 enclosures, others, especially in winter, in an aviary with warmed 

 interior. 



CiCONIID.E. No. of 



Indiv. 



Clconia, whole genus 56 



0. alba (White Stork) 34 



C. boi/ciana (Boyce's „ ) 2 



C. nigra (Black „ ) 20 



Dissiira episcopus (White-necked 12 



Stork). 



I), maguari (Maguari Stork) 10 



Ahdimia sphenorliyncha (White- 3 



bellied Stork). 



A'eaor^?/?ic/msaHs^raZis (Black-necked 11 18 68 



Stork). 



X. senegalensis (Saddle- billed ,, ). 4 



Myctei'ia americana (American 8 



Jabiru). 



Leptoptilus^ whole genus 19 



X. fw^rtZa (Indian Adjutant) 5 



L. a^umeniferus (Marabou Stork) ... 9 



L. javanicus (Javan Adjutant) 5 



Scopus umhretta (Tufted Umbre) ... 5 



Tantalus loculator (Ameiican 7 



Tantalus). 



Fseudotantahcs ibis (African ,, ). 13 



P. leucocephalus (Indian ,, ). 7 



Mr. J. H. Gurney (loc. cit. p. 38) cites well authenticated 

 records of a Black Stork of 30 years and a Jabiru of 36 years. 

 Nearly 19 years for an Adjutant is the highest on this list, 

 whilst the average durations vary, roughly in proportion to size, 

 from about 4 years to about 1 year. During part of the period 

 in consideration, the larger tropical Storks were kept in the 

 Antelope House, which was warmed in winter ; towards the end 

 of the period a new house was erected, in which there were 

 heated compartments leading to open-air paddocks to which the 

 birds were admitted at the discretion of the keepei^* — a discretion 

 usually exercised with a strong bias in favour of heat as opposed 

 to air. The intestinal tract is relatively long and of small calibre 

 but the hind-gut and cteca are very reduced. There appears to 

 be no good reason in the structure of these birds foi- the rela- 

 tively low viability which appears in the records. 



