LIMICO'L^ 357 



The foregoing table shows some of the principal points 

 in which the several families of the Limicolae differ from 

 each other, and will afford a justification for the divisions 

 aiopted in the present work. Whatever is the relation 

 between the other families, we can clear the ground by 

 removing the Laridae from competition for the basal place 

 in the series. As was discovered by Parkeb, the young of 

 •these birds have basipterygoid processes and occipital formina, 

 the persistence of which, therefore, in the Charadriidae and 

 Parridae (basipterygoids only) places those two groups lower 

 in the series than the more specialised gulls. That the gulls 

 are rightly placed here, and therefore as rightly removed from 

 a closer association with the Alcae, can hardly be disputed. 

 Gadow, who does the reverse^in his scheme, enumerates only 

 the following points in which the gulls differ froni the 

 Limicolae : — 



In the Laridae — - ''" 



Down feathers are thicker. Coracoids "in contact. Haem- 

 apophyses mostly {not in Lestris) wanting to the dorsal ver- 

 tebrae. Hypotarsus simpler. In muscle formula of leg dis- 

 appearance of B instead of Y. Webbed feet. 



As a matter of fact, the crossing of the coracoids in 

 (Edicnemus destroys the second of these, at best very slender, 

 grounds, and, as Gadow admits, the webbing is almost as well 

 developed in Becurvirostra. 



On the other hand the differences from the Alcse are 

 more pronounced. 



These latter birds have — 



A much longer sternum. 



Largely developed dorsal haemapophyses, of which in- 

 dications only are to be found in the gulls and in other 

 Limicolae. 



The biceps slip is peculiar. 



The leg muscles are always reduced, the formula being 

 in Phaleris only AX — . 



It may be mentioned in addition that the expansor 

 secundariorum is always absent in the Alcae and only some- 

 times in the Laridae. The auks are, in fact, so far as we 



