TUBINARES. 



FORKED-TAILED PETREL. 37 



PROCELLARIIDjE. 



Cymochokea. leucorehoa (Vieillot.)* 



THE FORKED-TAILED PETREL. 



Thalassidro7na Leachii. 



Cymochorea, Couesf. — Bill shorter than the head, moderately stout, com- 

 pressed, rising slightly at the unguis, then decurred ; nostrils tubular, dorsal. 

 Wings long and narrow ; the first quill-feather shorter than the second, which 

 is the longest, and also than the third, and about equal to the fourth. Tail 

 long and deeply forked. Legs short, slender ; tarsi anteriorly reticulate ; hind 

 toe minute, front toes long and slender ; webs slightly emarginate. 



The first British specimen of this Petrel was obtained at 

 St. Ivilda in the summer of 1818, by Mr. Bullock, during a 

 tour round the coast of Scotland, principally undertaken with 

 a view to investigate its ornithology. At the sale of Mr. 

 Bullock's collection in the spring of 1819, this specimen was 

 bought by Dr. Leach, and transferred to the national collec- 

 tion in the British Museum. At that time only three other 



* Procellaria leucorhoa, Vieillot, Nouv. Diet. xxv. p. 422 (1817). 

 t Pr. Ac. N. Sc. Philad. 1864, p. 76. The present species is the type of this 

 well-marked genus, two other members of which are found in the North Pacific. 



