The Ambiens is a muscle (so called by Sundevall, Forhandl. Skand.
Naturf. 1851, pages. 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. It has been argued that the taxonomic
value of this muscle has been much over-estimated since Garrod (P. Z.
S. 1874, pp. 111-123) divided the Class into Homalogonatae, birds possessing
an ambiens muscle, and Anomalogonatea, or birds without such a muscle.
The muscle is typically developed in:
It is absent in:
It is very variable in:
See also Muscular system.
Also spelt Amadavat, or Avaduvat, the name given to a well-known favourite
cage-bird, Estrilda amandava (see Weaver-Bird), being a corruption
of Ahmadabad, the name of a town in Goojerat whence, more than 300 years
ago, according to Fryer (New Account of East India, &c., London:
1698), examples were 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."
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 Embryology).
The amnion affords one of the principal differentiating characters in the
vertebrata; Reptiles, Birds, and Mammals are as Amniota (Haeckel,
opposed to Amphibians and Fishes or Anamnia.
A group of birds so called by Nitzsch in 1829 (Observationes de Avium
Carotide communi, p. 16) comprising the genera, as then understood,
(MOUSE- BIRD), and Opisthocomus
(HOACTZIN); but by no means
to be confused with the Amphiboli (see below).
One of Illiger's groups, defined in 1811 (Prodromus Systematis Mammalium
et Avium, p. 203), and composed of the genera Crotophaga, Scythrops,
Bucco, Cuculus and Centropus- the third of which is treated
of under the titles of Barbet and Puff-Bird, while the rest will be found
under those of Ani, Channel Bill, and Cuckoo.