340 THE ZOOLOGIST. 



squeamish ; for sometimes the gulls must, when they have 

 nothing on the market-place, open the back door and throw at 

 him spoiled food, which he takes for good as well. Swartlasse 

 is very adroit, so that he always catches the food in the air when 

 it is thrown at him by the gull. Nor is he shy, for when the 

 fishermen see him, and cry, ' Elof, Elof,' with outstretched arm, 

 and showing him some little fish, Elof comes flying towards the 

 boat, and catches the fish as soon as it is thrown." . . . 



That every word of this description applies to the Common 

 Skua, and not to the Long-tailed, is apparent to everyone who 

 has any knowledge about these birds. The Long-tailed Skua is 

 also not to be found on the Swedish west coast, where Linnaeus 

 made these observations, but where the Common Skua is not 

 scarce. 



The third of the quotations from ' Systema Naturae ' refers 

 to Nils Gissler's account, as is already mentioned. This con- 

 spicuously refers to the Common Skua (not the Long-tailed). 

 The following points are conclusive. Gissler mentions the 

 dimorphism of the Skua, although he erroneously believes it to 

 be a sexual dimorphism, and says that the male is more blackish. 

 It can nevertheless not be referred to the Long-tailed Skua,* 

 for it does not coincide with the information that the bird in 

 question lays its two eggs on the uttermost rocks in the archi- 

 pelago, while the Long-tailed species in Scandinavia only breeds 

 on the fells of Lapland and adjoining parts. Thereafter Gissler 

 describes the parasitic habits of the bird — how it robs the 

 Gulls, &c. ; how rapid and dexterous it is in its flight, and 

 how it can be attracted by the fishermen throwing at it a 

 herring, or some other eatable thing, and so on ; all facts refer- 

 able to the Common Skua, and only to that species, not to the 

 Long-tailed one. These three references are, as already men- 

 tioned, quoted in the first place, and are the more important 

 because they are partly Linnseus's own — must have been so 

 thoroughly understood by him — as they were made by a con- 

 temporary author about a well-known Swedish bird. When 

 this is so it is perfectly evident that Linnseus, with his Larus 

 parasiticus, meant the Common Skua, which he himself had seen, 



* Only one instance of dimorphism being known about the Long-tailed 

 Skua. 



