9G8 



5 YS TEMA TIC S Y NOP SIS. — S TE GA NOP ODES. 



Family ANHING-ID^ : Anhingas; Darters; Snake-birds. 



(Formerly Plotid^.) 



Bill about twice as long as head, straight, slender, very acute, paragnathous ; tomia with 

 fine serratures. Gular sac moderate, naked. Nostrils minute, entirely obliterated in adult. 

 Wings moderate; 3d quill longest. Tail rather long, stifi', broad, and fan-shaped, of 12 feath- 

 ers widening toward end ; outer web of middle pair curiously crimped. 



There is an occipital style, as in Cormorants, but it is very small, and not always ossified. 

 There are remarkable peculiarities of the cervical vertebrse, in their conformation and articula- 

 tion, the passage of tendons through bony eyelets, etc. — a mechanism producing the strong 

 kink observable near middle of neck, and ability of the bird to thrust forward and retract the 

 head. Cervical vertebrae 20 ; the kink begins at the 8th ; the 22d-25th vertebrae are opistho- 

 coelous. The digestive system shows a remarkable feature ; instead of the lower part of the 

 oesophagus being occupied by proventricular glands, these are placed in a small distinct sac on 

 right side of gizzard, which, as in other Steganopodes, develops a special pyloric cavity, the 

 orifice of which "is protected by a mat of lengthy hair-like processes, much like cocoa-nut 

 fibre, which nearly half fills the second stomach." There is a single small coecum, as in Herons, 

 in our species, but a small pair in another. The tongue is very rudimentary and almost obso- 

 lete. Carotid single. Pterylosis peculiar in reduction of apteria to a lateral pair on the trunk 

 and one narrow inferior space. Subcutaneous tissue not emphysematous. Sternum as in 

 Cormorants. 



Darters are birds ot singular appearance, somewhat like Cormorants, but much more 

 slightly built, and with exceedingly long slender neck and small constricted head that seems 

 to taper directly into the bill, the head, neck, and bill resembling those of a Heron. As in 

 Cormorants, there are long slender feathers on neck ; sexes commonly distinguishable, but 9 



sometimes resem- 

 bles ^. Other 

 changes of plu- 

 mage appear to be 

 considerable, but 

 not well made out. 

 The feet are short, 

 and placed rather 

 far back, but the 

 birds perch with 

 ease. Unlike most 

 of the order, they 



are not maritime, shunning the seacoast, dwelling in the most impenetrable swamps of warm 

 countries. They fly swiftly, and dive with amazing ease and celerity. They are timid and 

 vigilant ; when alarmed they drop from their perch into the water below, noiselessly and with 

 scarcely a ripple of the surface, and swim beneath the surface to a safe distance before re- 

 appearing. When surprised on the water, they have the curious habit of sinking quietly back- 

 ward, like Grebes ; and they often swim with the body submerged, only the head and neck in 

 sight, looking like some strange kind of water-serpent ; whence the names Snake-bird and 

 Anhinga. They feed on fish, which they do not dive down upon, but dive for and pursue 

 under water like Cormorants and Loons. Eggs 2-5, pale bluish, with white chalky incrusta- 

 tion. There are only 4 species: the African P. rufus, congensis or levaillanti; the Indian 

 P. melanogaster ; the Australian P. novce-Jiollandice ; with the following: 



Fig. G79. —American Darter. (L. A. Fuertes.) 



