HYPOTHETICAL LIST. 1 



FAMILY ALCID-ffi. 



Cepphus motzfeldi (BENICKEN). Black-winged Guillemot. [2.] 

 Uria motzfeldi BENICKEN, Isis, XV, 1824, 889. (Greenland Seas.) 



North American, but its specific validity not satisfactorily estab- 

 lished. (Cf. STEJNEGER, Proc. U. S. Nat. Mus., VII, 1884, 210; 

 Water Birds N. A., II, 1884, 497, 498). 



FAMILY LARID-ffi. 

 GENUS CREAGRUS BONAPARTE. 



Creagrus BONAPARTE, Naumannia, 1854, 213. Type, by orig. desig., 

 Larus furcatus NEBOUX. 



Creagrus furcatus (NEBODX). Swallow-tailed Gull. [4.] 



Larus furcatus NEBOUX, Zool. Voy. Venus, Atlas, 1842, pi. 10. ("Mon- 

 terey," California.) 



In all probability erroneously accredited to North America. 



1 Consisting of species which have been recorded as North American, but whose status 

 as North American birds is doubtful, either from lack of positive evidence of their occur- 

 rence within the prescribed limits of the present Check-List, or from absence of satis- 

 factory proof of their validity as species. 



