1876.] NEOTROPICAL ANATID.E. 403 



Mr. Darwin, in describing its habits, says that its wings are too 

 small and weak to allow of flight, but that by their aid, partly swim- 

 ming and partly flapping the surface of the water, it is enabled to 

 move very quickly. He adds that he is nearly sure that it moves 

 its wings alternately instead of, as in the case of other birds, both 

 together. It. is able to dive only a short distance. It feeds on mol- 

 lusks, obtained from floating kelp and tidal rocks. 



Dr. Cunningham remarks that the Loggerhead Duck is very 

 plentiful in the eastern part of the Straits of Magellan, and that it 

 also occurs in abundance at the Falkland Islands. He adds that the 

 bird is exceedingly hard to kill. 



In the latter islands Capt. Abbott found them in great numbers, 

 where they breed along the coast. The nests are readily found by 

 searching the shore just opposite where the male bird is seen swim- 

 ming by himself. The old female flutters off to the water, being 

 cpiite unable to fly. It lays from the end of September to the end 

 of November, making its nest in the long grass or a bush of some 

 kind. The usual complement of eggs is seven, as many as nine 

 being sometimes found. 



The " Flying Loggerhead " is probably the young bird of this 

 species, though it would appear from Capt. Abbott's remarks that it 

 breeds when still able to fly ; for one flew out of a nest that he 

 found, high up into the air. Capt. Abbott considers the flying bird 

 distinct ; but Dr. Cunningham's view seems to be the correct one, 

 viz. that "the so-called M. patachonicus is only the young of M. 

 cinereus, the peculiarity being that the power of flight departs from 

 the bird as it grows old" *. 



The anatomy of this Duck is fully described in Dr. Cunningham's 

 memoir in the Society's ' Transactions.' 



Subfamily V. Erismaturin^e. 



Genus Erismatura. Type. 



Oxyura, Bp. Syn. N. A. Birds, p. 390 (1828) E. rubida. 



Gymnura, Nuttall, Man. Ornith. ii. p. 426 (1834) .. E. rubida. 



Undino, Gould, B. of Eur. vol. v. pi. 383 (1836) . . E. mersa. 



Erismatura, Bp. Comp. List, p. 59 (1838) E. mersa. 



Cerconectes, Wagler, Ibis, 1832, p. 282 E. mersa. 



Bythonessa, Gloger, Handb. d. Nat. p. 4/2 (1842) . . E. mersa. 



Of the three species of this quasi-cosmopolitan group one is only 

 found in the northern part of the Neotropical region, a second is very 

 widely spread in tropical America, and the third may be regarded as 

 an Antarctic form. 



1. Erismatura rubida. 



Anas rubida, Wils. Am. Orn. vii. p. 128, t. 81 (1814). 



Erismatura rubida, Bp. Comp. List, p. 59 ; Baird, Bird of N. A. 

 p. 81 1 ; Eyton. Mon. Anat. p. 171 ; Gundl. Repert. F.-N. i. p. 390, 

 et J. fur Orn. 1875, p. 384 (Cuba); Cab. J. fiir Orn. 1857, p. 230 

 * See P. Z. S. 1871, p. 262, and Tram. Zool. Soc. vii. 493. 



