CAPBIMULGID^ : GOATSUCKERS. 
447 
lower end of the metatarsus, corresponding to the reversed position of the fourth toe, 
and the upper part of the same bone is perforated by 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 Picarice) ] the tail 10 rectrices, soft and 
rounded in lyngidce and Picumnidce, rigid and acuminate in Picidee, 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 lyngidcB, usually covered with 
antrorse plumules in the rest. The bill is straight or nearly so, hard and strong, 
acute or truncate, the mandibles equal; the tongue is lumbriciform, 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 nearly than other Picarice do. 
However impossible it is to define any such group as the conventional Picarice, and how- 
ever difficult 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 families his specimen belongs. 
3. Suborder CYPSELIFORMES : Cypseliform Birds. 
Fissirostral {Caprimulgidce, Cypselidce) or tenuirostral {Trochilidce) Picarice. 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 ; small, 
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. 172). Sternum 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 Cypselidce and Trochilidce ; coeca present in 
Caprimulgidce. 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 Caprimulgidce, in essential 
structural characters. 
21. Family CAPRIMULGID^ : G-oatsuckers 
(So called from a traditional superstition). 
Fissirostral Picarice. Head broad, flattened ; 
neck inappreciable; eyes and ears large. Bill 
extremely small in its horny 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 
Fig. 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 
