S6 BIRDS OF BRITISH GUIAN'A. 



Fig. IS.— To illustrate tlit- peculiar l.ill. 



52. Cymocliorea leucorlioa. 



Fork-tailed Petrel. 



Cymochorea leucorlioa (Yieill.), N. Diet. d'Hist. Xat. xxv. p. 422, 1S17 

 ("a trouve sur les bord.s maritime.s de la Picardie "). 



Oceanodroma Ipucorrhoa Salvin, Cat. B. Brit. Mus. xxv. p. .348, 1896 ; 

 Chubb, Bull. Brit. Orn. Club, xxxi. p. 39, Janmiiy 1913 (Essequebo 

 River). 



Adult. Sooty-brown above and below, with a greyish tinge on 

 the head; a grey band across the ^^ing; upper tail-coverts 

 white ; under tail-coverts inclining to white at the base. Bill 

 and feet black. 



Total length 203 mm., cnlmen 15, wing 169, tail C5, lateral 

 feathers 87, tarsus 2.5, middle toe and claw 24. 



The bird from which the description is taken was obtained on 

 the Warima River, Essequebo. 



Breeding-season. Unknown in British Guiana. 



yest. Unrecorded in Britisli Guiana. 



Efjg. Undescribed from British Guiana. 



liange in British Guiana. Warinia River, Essequebo River 

 {McConnell collection). 



E.rtraliniital liange. Seas of the Northern Hemisphere. 



Habits. Unrecorded in British Guiana. 



This is the first and only record of this species in British 

 Guiana, but it has been recorded from Surinam (c/r. Penard, 

 Yogels Guyana, i. p. 58). 



Order LARIFORMES. 



Family LARIDJ^, 



AVe include in this family the Terns, Gulls, and Skuas. The 

 Terns are generally distinguished bv their pointed bills and forked 

 tails, the Gulls by their stouter bills and square tails, and the Skuas 

 by their hooked bills and pointed tails. 



