353 Recently published Ornithological Works. 



to the attack of enemies, and that among birds wliich do 

 not appear to be specially so liable, sexual dimorphism is 

 rarely, if ever, present. He divides the bird-families of the 

 world into five groups, according to what he believes to 

 be their relative vulnerability to enemies, as follows : — 

 terrestrial, arboreal, aerial, aquatic, and oceanic. The first 

 of these groups is the most vulnerable, the oceanic the least, 

 and Mr. Mottram finds that the proportion of birds exhibiting 

 sexual dimorphism is far the greatest in the first group, where 

 at least 38 per cent, of the families show this trait more or 

 less, while among the oceanic group there is practically no 

 sexual dimorphism. 



There are a number of other tables given with a view to 

 prove this thesis, but the author does not attempt to give 

 any reason for this correlation between sexual dimorphism 

 and vulnerability, nor are we satisfied that it is possible to 

 divide birds into classes according to this last characteristic. 

 We hardly know sufficiently well the habits of birds to 

 estimate the amount of their vulnerability, and, unless we 

 can make sure of this foundation, it appears to us that tiie 

 whole of the argument fails. 



Van Oort's recent papers. 



[Resultaten van het ringonderzoek vau het Rijks Museum te Leiden. 

 Door Dr. E. D. vau Oort. Ardea, Leiden, 1915, pp. 119-126. 



Een voor Nederlandscbe fauna nieuwe stormvogelsoort, Pujinus 

 gravis (O'Reilly). Door Dr. E. D. van Oort. Ardea, Leiden, 1915, 

 pp. 130-1. 



On a new Bird-of-Paradise from Central New Guinea, Falcinellus 

 meijeri albicans. By Dr. E. D. van Oort. Zoologische Mededeelingen, i. 

 1915, p. 228.] 



In the first of these papers Dr. van Oort gives a list of 

 birds which had been ringed in Holland and were recovered 

 during the year 1915. The list is not a long one, and there 

 are no very remarkable recoveries. Of three Lapwings, one 

 was reported from Fez, another from southern Spain, and 

 two Black-headed Gulls, ringed respectively in June 1911 

 and 1913 in Holland, were killed in February 1915 in 

 Portugal. 



