AMAZON— AMNION ii 



h. Higher Nidicolae, — liatclied in a helpless condition, blind ; 

 mostly naked, and for a long time nursed in the nest, the 

 food -yolk having been used up at birth: — Golumbse, 

 Striges, Accipitres, Psittaci, Coccyges, Epopes, Haley ones, 

 Cypselomorphsa, Pici, Passcres. 

 The two series a and b stand phylogenetically parallel to each other. 



AMAZON, a bird-fanciers' name for a certain group of Parrots 

 belonging chiefly to the genus Chrysotis. 



AMBIENS is a muscle (so called by Sundevall, F'arhandl. Skand. 

 Naturf. 1851, pp. 259-269 : abstract in Rep. Brit. Assoc. 1855, Trans, 

 of Sect. p. 137) which, arising from the pectineal process of the pelvis, 

 runs along the inner surface of the thigh, passes the knee as a 

 string-like tendon, and then forms one of the heads of the deep 

 flexor muscle of the second and third toe. The taxonomic value 

 of this muscle has been much over-estimated since Garrod (P. Z. S. 

 1874, pp. 111-123) divided the Class into HoMALOGONAT^, birds 

 possessing an ambiens muscle, and ANOMALOGONATiE, or birds 

 without such a muscle. The muscle is typically developed in 

 Crypturi, Gallinse, Pteroclidse, Gralla3, Laridse, Colymbidse, Stegano- 

 podes, Impennes, Anseres, Accipitres, Coccyges ; it is absent in all 

 Striges, Cypselomorphre, Halcyones, Epopes, Trogonidse, Pici, Pas- 

 seres, Herodii, Alcidse, Podicipedidffi ; it is very variable in Eatitse, 

 Pelargi, Tubinares, Columbse, Psittaci (see also Muscular System 

 and Introduction). 



AJMIDAVAD, otherwise AMADAVAT, or AVADUVAT, the 

 name given to a well-known favourite cage-bird, Estrilda arnandava 

 (see Weaver-bird), being a corruption of Ahmadabad, the name of 

 a town in Goojerat whence, more than 200 years ago, according to 

 Yvjev {New Account of East India, &c., London: 1698), examples 

 Avere brought to Surat. In his peculiar style he tells us (p. 116) 

 that " they are spotted with White and Red, no bigger than Measles, 

 the principal Chorister beginning, the rest in Concert, Fifty in a 

 cage, make an admirable Chorus." 



AMNION (a Greek word of doubtful derivation, used already 

 by Aristotle). From either end of the body of the very early 

 embryo grows out a fold which passes dorsally over the embryo, 

 and unites above it with its fellow from the other end ; between 

 the two layers of this double fold, which is the amnion, extends 

 the body-cavity, and receives the rapidly-growing Allantois ; the 

 outer membrane of the allantois fuses with the outer double fold of 

 the amnion, and forms the chorion, lining the eggshell (see Embryo- 

 logy). The amnion affords one of the principal differentiating 

 characters in the vertebrata ; Eeptiles, Birds, and Mammals are as 

 Amniota (Haeckel, Anthropogenie, 1874) opposed to Amphibians 

 and Fishes or Anamnia 



1 J^isnes or Anamma. . . /) J / ^ / ^ / 



