628 MANUAL OF ZOOLOGY. 



females generally sombre. The legs are short and weak, but 

 the wings are proportionately very long, and the flight is 

 exceedingly rapid. 



The Sun -birds represent in the Old World the Hum- 

 ming-birds of the western hemisphere, and the Australian 

 Honey-eaters show also many points of resemblance to the 

 Trochilidce. 



Sub-order 4. Fissirostres. In this sub-order of the Insessores 

 the beak is short but remarkably wide in its gape (figs. 345, C, 

 and 347), and the opening of the bill is fenced in by a number 

 of bristles (vibrissce). This arrangement is in accordance with 



the habits of the Fissi- 

 rostres, the typical mem- 

 bers of which live upon 

 insects and take their prey 

 upon the wing. The most 

 typical Fissirostral birds, 

 in fact, such as the Swal- 

 lows and Goatsuckers, fly 

 about with their mouths 

 widely opened; and the 

 insects which they catch 

 in this way are prevented 

 Fig. sTr.-Head of Goatsucker (Ca^nui^, fr escaping partly by 



showing the fissirostral form of beak. the bristles which border 



the gape, and partly by a 

 viscid saliva which covers the tongue and inside of the mouth. 



The group of the Fissirostres, with various additions (notably 

 with that of the Humming-birds), is often raised to the rank of 

 a distinct order (the Volitores of Professor Owen). 



The typical Fissirostres, characterised by the structure of 

 the beak, comprise three families the Swallows and Martins 

 (Hirundinida), the Swifts (Cypselida*), and the Goatsuckers 

 (Caprimulgidce). These three families differ in many important 

 respects from one another, but it would be inconvenient to 

 separate them here. The Swifts, especially, are remarkable 

 for the peculiarity that whilst the hallux is present, it is turned 

 forwards along with the three anterior toes. The Goatsuckers, 

 again, hunt their prey by night, and they are provided with 

 the large eyes and thick soft plumage of all nocturnal birds. 

 Besides the above, there remain the two families of the King- 

 fishers and Bee-eaters, which are generally placed amongst the 

 Fissirostres, though in very many respects the arrangement 

 appears to be an unnatural one. These families are charac- 

 terised by their stronger and longer bills, and by having the 



