MONOGRAPH OF THE PETRELS. 



. The males are generally a little larger than the females. The variation in the 

 amount of the white quill-lining in the true P. Icuhli of the Mediterranean has been 

 already alluded to, and in the Atlantic birds an equal variation is met with. Thus, 

 a specimen from Porto Santo, obtained by Padre Schmitz, ought to have a dark quill- 

 lining, but shows some white on the second and third primaries, which extends more 

 than half-way down the quill. A Tenerife specimen is similar. 



The records of the colours of the bill and feet vary to a considerable extent. Those 

 in a specimen from the Azores are given by Mr. Ogilvie-Grant as follows : — " Bill 

 yellowish-horn, the nostrils and tip of rhampotheca dusky ; legs pale flesh- 

 colour, blackish on outer side of tarsus, outer toe, joints, and webs." A bird 

 obtained by the same observer on Great Salvage Island had the " bill dirty- 

 yellow, the culmen and the tips of the cutting-edges blackish-brown ; legs pale 

 flesh-colour ; outer toe-joints and webs dusky ; inner toe and nail very pale 

 flesh-colour ; iris dark brownish-black." Another bird, from Deserta Grande, is 

 recorded by Mr. Ogilvie-Grant as having the " bill dull yellow, darker towards 

 the tip ; legs and feet pale pink, the outer toe and the webs dusky ; iris dark 

 brown." In the type of P. borealis from Cape Cod, Mr. C. B. Cory states that the bill 

 was " pale yellowish at the base, shading into greenish-black, but again becoming pale 

 near the tip : outside of feet greenish-black, the inside and webs dull orange." 



The specimen described is one obtained by the late Edward Cavendish Taylor near 

 Genoa, and now in the British Museum. The bird figured was procured by myself 

 in the Azores. 



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