CAPEIMULGIDM : GOATSUCKERS. 447 



lower end of the metatarsus, corresponding to the reversed position of the fourth toe, 

 and the upper part of the same hone is perforated hy canals for flexor tendons. The 

 basal phalanges of the toes are short. The wing has 10 primaries, and short 

 secondary coverts (contrary to the rule in Picwrim) ; the tail 10 rectrices, soft and 

 rounded in lyngidee and Picumnides, rigid and acuminate in PiddcB, where also a 

 supplementary pair of spurious feathers is developed, making 12 in all. The nostrils 

 vary: they are large and of peculiar structure in lyngidtB, usually covered with 

 antrorse plumules in the rest. The hill is straight or nearly so, hard and strong, 

 acute or truncate, the mandibles equal ; the tongue is lumhriciform, and very gener- 

 ally extensile to a remarkable degree, by a singular elongation of the bones and 

 muscles (figs. 73, 74). The structure of the bony palate is unique among birds ; it 

 is called saurognathous by Parker (see p. 173). The salivary glands have an 

 unusual development, in the typical species at any rate. The sternum is doubly- 

 notched behind. A very strongly-marked group ; in some respects it approaches the 

 Passerine birds more neai'ly than other Picariee do. 

 However impossible it is to define any such group as the conventional Picariee, and how- 

 ever difiicult it may be to make three or any other small number of subdivisions, the very 

 diversity of the forms enables us to define the families with ease. The student can never be in 

 doubt to which one of the six North American /amifos his specimen belongs. 



3. SuBOBDER CYPSELIFORMES : Ctpseliporm Birds. 



Fissirostral {Caprimulgidce, Cypselidts) or tenmrostral (Trochilidce') Picaria. Wings 

 lengthened in the distal joints, shortened in the proximal, with 10 fully-developed primaries ; 

 making an instrument of remarkable power. Feet never zygodactyle nor syndactyle ; smaU, 

 weak, scarcely fitted for progression ; hind toe often elevated or versatile ; front toes often 

 webbed at base, or with abnormal ratio of phalanges, or both these modifications together 

 (figs. 40, 41). Tail of 10 rectrices. Palate segithognathous (p. 173). Stei-num deep-keeled, 

 its posterior border usually entire, or doubly-notched or fenestrate. Syringeal muscles not more 

 than one pair. The oil-gland nude. No coeca in Oypselidee and Trochilidce ; coeoa present in 

 CaprimulgidcB. Anomalogonatous ; no ambiens nor accessory femoro-caudal muscle. 



Contains the 3 families named above, — Goatsuckers, Swifts, and Humming-birds. Not- 

 withstanding the peculiarities of the latter, especially their long slender bill, they are really more 

 nearly related to the fissirostral Swifts than these are to the fissirostral CaprimulgidcB, in essential 

 structural characters. 



21. Family CAPRIMULG-ID^ : Goatsuckers 



(So called from a traditional superstition). 

 Fissirostral Picariee. Head broad, flattened ; 

 neck inappreciable; eyes and ears large. Bill 

 extremely small in its homy portion, which is 

 depressed, and triangular when viewed from 

 above, but with enormous gape reaching be- 

 low the eye, and generally with bristles attain- 

 ing an extraordinary development. Nostrils 

 Pie. 289. — Whippoorwill, a setirostral Caprimul- basal, exposed, roundish, with a raised border, 

 gine. (From Tenney, after Wilson.) sometimes prolonged into a tube. . Wings 



more or less lengthened and pointed, deriving their sweep mainly from elongation of the distal 

 joints and the feathers, the proximal segment being short ; of 10 primaries and more than 9 

 secondaries ; the latter not so extremely short as in Cypselidce. Tail variable in shape, of 10 



