PALM SWIFT. 59 



the black body, is a very common species in Jamaica, 

 where it resides all the year. Over the grass-pieces 

 and savannas of the lowlands, the marshy flats at 

 the seaward mouths of the valleys, as well as the 

 pens of the mountain slopes, this swift-winged sylph 

 daily urges its rushing course in parties of half-a- 

 dozen to fifty or a hundred, often mingled with 

 other Swallows, performing mazy evolutions, circling 

 and turning, crossing and recrossing, now darting 

 aloft, now sweeping over the grass, till the eye is 

 wearied with attempting to follow them. The 

 length of its wings, which is scarcely less than that 

 of the whole bird, renders it a fleet and powerful 

 flier ; an attentive observation will be able to identify 

 it, when mingling in aerial career, by a more frequent 

 recurrence of the rapid vibration of the wings, the 

 momentary winnowing, by which a fresh impetus 

 is gained. There is a very interesting structure in 

 the sternum of this bird, which as far as I know is 

 unprecedented. The sternum, though void of emar- 

 ginations, possesses two oblong foramina of large 

 size, one on each side of the middle of the ridge, 

 and a round one perforating the ridge itself near 



Irides dark hazel ; beak black ; feet purplish flesh-colour ; claws horn- 

 colour ; inside of mouth, flesh-colour, tinged in parts with bluish. Head 

 smoke brown, paling on the sides ; back, wings, tail-coverts, and tail, 

 sooty-black, unglossed, or with slight greenish reflections on the tail. 

 Across the rump a broad band of pure white, the black descending into 

 it from the back, in form of a point ; sometimes dividing it. Chin and 

 throat silky white, the feathers brown at the base ; sides smoky-black, 

 meeting in a narrow, ill-defined line across the breast ; medial belly 

 white. Thighs, under tail-coverts, and inner surface of wings smoky - 

 black. 



