STEGANOPODES 413 



The relationship of the clavicles to the scapula and to the 

 coracoid, upon which Furbeingbe has laid so much stress, 

 serves to differentiate some of the Steganopodes. In Plotus 

 the clavicle is connected by ligament vdth the scapula ; this 

 connection is nearly effected in Phalacrocorax and Sula, but 

 not in Pelecanus. In Fregata the dilated end of the clavicle 

 is perforated in the middle ; it is, moreover, fused with the 

 scapula. 



The genus Plotus (consisting of the four species P. anhinga, 

 P. melanog aster, P. Novm Hollandia, and P. Levaillanti) has been 

 investigated by Brandt,' Eyton,^Donitz,'Gaebod,'' Poebes,^ Fub- 

 BEiNGEE,* and myself. Many of its characters have been described 

 in the foregoing pages. I shall here direct attention to certain 

 peculiarities of Plotus which it does not share with the other 

 Steganopodes, or which it possesses in a more marked degree than 

 its nearest "ally, Phalacrocorax. The darters feed in a peculiar 

 manner ; they pursue fishes under water with a jerky action of the 

 head and neck. This action, as Mr. Poebes has suggested, may 

 be compared to that of a man poising a spear before hurling it. 

 ' Arrived within striking distance,' continues Mr. Foebes, ' the 

 darter suddenly transfixes — in fact, bayonets — the fish on the tip of 

 its beak with marvellous dexterity, and then immediately comes 

 to the surface, where the fish is shaken off the beak by jerking of 

 the head and neck, thrown upwards, and swallowed, usually bead 

 first.' This mechanical action is associated with a mechanism in 

 the neck/ 



The first eight vertebrae form a continuous curve forwards, so 

 marked that the head- when outstretched is in the same straight 

 line with the eighth vertebra. This latter vertebra is articulated 

 at right angles with the foregoing, and almost at right angles with 

 that which follows ; there is thus formed a conspicuous kink in 

 the neck, which is never unbent. 



' hoc. cit. (on p. 409.) ' Osteologia Avium, p. 218. 



" ' Ueber die Halswirbelsaiale der Vogel,' &c., Arch. f. Anat. u. Phys. 1873, 

 p. 357. 



* ' Notes on the Anatomy of Plotus cmMmga,' P. Z. S. 1876, p. 335, and 

 ' Note on Points in the Anatomy of Levaillant's Darter (Plotus Levaillanti),' ibid. 

 1878, p. 679. 



* ' On some Points in the Anatomy of the Indian Darter,' &c., ibid. 1882, 

 p. 208. 



" 'Notes on the Anatomy and Osteology of the Indian Darter (Plotus 

 melanogaster),' ibid. 1892, p. 291. 



