608 



CYPSELIN^E. 



whereas in the latter the crest is less raised, and the posterior 

 margin deeply notched, as in the Cantatores and Excursores, in 

 which the skeleton is otherwise very similar. Indeed the affini- 

 ties of these birds are very complex ; but for the present occa- 

 sion it will suffice to shew that in the British series, the Cyp- 

 selinae are intermediate between the Hirundinae and Caprimul- 

 ginse. 



SYNOPSIS OF THE BRITISH GENERA AND SPECIES. 



GENUS I. CYPSELUS. SWIFT. 



Bill very small, weak, opening to beneath the hind part of 

 the eye, much compressed at the end ; gape-line arched ; nos- 

 trils oblong, marginate ; wings extremely long, falciform ; tail 

 of ten feathers, emarginate or forked ; tarsus very short, fea- 

 thered ; all the toes directed forwards, and having only two 

 phalanges, three of them nearly equal ; claws stout, decurved, 

 acute. 



1. Cypselus Melba. White-bellied Sioift. Greyish-brown, 

 with the throat, breast, and abdomen, white. 



2. Cypselus murarius. Black Swift. Brownish-black, with 

 the throat whitish. 



