202 



MR. H. SAUNDERS ON THE EARING. 



[Feb. 5, 



Xema cirrhocephala ?, Gray, List Birds Brit. Mus. iii. p. 1 73 (] 844), 

 partim (East Patagonia). 



Chroicocephalus maculipennis, Bruch, J. f. Orn. 1853, p. 105. 



Gavia maculipennis, Blasius, J. f. Orn. 1865, p. 374. 



" Larus s err anus, Tsch.," Burmeister, La Plata-Reise, ii. p. 519 

 (1861), nee Tschudi (Entre Rios, Mendoza). 



Larus cirrhocephalus, Hudson, P. Z. S. 1870, p. 802; id. P. Z. S. 

 1871, p. 4, nee Vieillot. 



Larus glaucodes, Saunders, P. Z. S. 1874, p. 294 (partim). 



Hab. Chuput valley, North-east Patagonia (breeding), up to the 

 La Plata, the Argentine Provinces, Mendoza, Entre Rios, Uruguay, 

 and the south coast of Brazil. 



Fig. 13. 



1. 2. 3. 



Three outer primaries of L. maculipennis, old. 



Burmeister's description of the bird which he calls L. serranus 

 clearly applies to this species ; the dimensions (length 1 2 in., wing 

 1 1 in., tarsus 2 in.) exactly suit it, whilst the wing of true L. sei'ranus 

 is over 14 in. long. 



The distinction between this species and the next, L. glaucodes, 



seems to rest upon the patterns of the primaries, as shown in the 



drawings (tigs. 13 and 14). In L. maculipennis the black forms a 



bar ; in L. glaucodes it is a mere border : and this is perfectly constant. 



[48] 



