42 Mr. W. Eagle Clarke — Ornithological 



Prof. Newton, to whose assistance I am in many ways 

 indebted, has drawn attention to Dr. Weismann^s ' Essays 

 on Heredity/ particularly one on the duration of animal 

 life, where the uniformity with which birds maintain their 

 numbers, which I have before referred to, is dwelt upon, and 

 several other questions bearing on the age of birds. Dr. Weis- 

 mann is of opinion that all birds and mammals outlive the 

 period of reproduction, but in the case of birds the facts I 

 have collected rather show the contrary. He also thinks 

 that only in the largest mammalia — whales and elephants — 

 is the duration of life equal to the longest-lived birds, but 

 on this head we require more facts. 



So far as birds are concerned, the points on which further 

 information is wanted are principally : — 



1. Are birds of some families longer-lived than those of 



others ? 



2. Do female birds live longer than males ? 



3. Are birds which are long in their incubation therefore 



long-lived ? 



4. Do large birds live longer than small ones ? 



5. Do birds in general live as long as mammals ? 



6. Do birds which lay only one egg live longer than birds 



which lay ten ? 

 Reference may also be made to Prof. Ray Lankester's 

 work on the ' Comparative Longevity in Man and the Lower 

 Animals.^ 



V. — An Epitome of Dr. Walter's Ornithological Results of a 

 Voyage to East Spitsbergen, in the Year 1889 *. By 

 "William Eagle Clarke, F.L.S. 



This valuable paper on the birds observed by the Expedi- 

 tion to East Spitsbergen promoted by the Bremen 



* " Oruithologisclie Ergebnisse der von der Bremei* geographischen 

 Gesellscliaft im Jahre 1889 veranstalteten Eeise nach Ostspitzbergen. Vou 

 Dr. Alfred Walter. (Aus dessen hinterlassenen Notizen bearbeitet vou 

 Prof. Dr. Willy Kiikeuthal.) " Journal fiir Ornithologie, xxxviii. Jahrg. 

 No. 190, pp. 233-255 (April 1890). 



