LEACH'S STORM-PETREL. 455 



M. Temmlnck's name. Dr. Fleming gives, as part of the 

 specific character, " the wings, when closed, not extending 

 beyond the tip of the tail ;" and Mr. Jenyns, " the wings not 

 reaching beyond its tip ;" but these authors, I suppose, had 

 not examined a fresh specimen, and in the one which I was 

 so fortunate to procure, the wings extended half an inch 

 beyond the longest tail-feathers. This was also the case with 

 a fresh male measured by Mr. Audubon : " length to end of 

 tail 8 inches ; to end of wings 8^." 



This species differs from Wilson's Petrel in being larger, 

 in having the bill stronger, the tail forked instead of even, 

 and the interdigital webs black instead of yellow and black. 

 It has no chance of being mistaken for Thalassidroma pela- 

 gica, which is very much smaller, with the tail rounded. If 

 such differences in the form of the tail are merely specific in 

 their genus, Avhy should they be held as generic in analogous 

 cases, but because system-makers are often very poor logicians ? 



