350 GLOS SARY. 
AMPHIDISC¢S (Gr. amphi, at both ends; diskos, a quoit, or round plate). The 
spicules which surround the reproductive ‘‘gemmules” of Spongilla, 
and resemble two toothed wheels united by an axle. . 
AMPHIOXuUS (Gr. amphi, at both ends ; oxus, sharp). The Lancelet, a cur- 
ious little fish, which alone constitutes the order Pharyngobranchti. 
AmMPHIPODA (Gr. amphi; and podes, feet), An order of the Crustacea, 
so called because some of the feet are directed forwards and some back- 
wards. 
Awnatogous. Applied to parts which perform the same function. 
ANARTHROPODA (Gr. a, without ; arthros, a joint ; podes, feet). The divi- 
sion of Annulose animals in which there are no articulated appendages. 
ANNELIDA (a Gallicised form of Annulata, Lat. annulus, a ring). The 
Ringed worms, which form one of the divisions of the Anarthropoda. 
ANNULOIDA (Lat. annulus, a ring; Gr. eidos, form). The sub-kingdom 
comprising the Hchinodermata and the Scolecida. 
ANNULOSA (Lat. annulus, a ring). The sub-kingdom comprising the 
Anarthropoda and the Arthropoda or Articulata, in all of which the body 
is more or less evidently composed of a succession of rings. : 
ANomoponv'rA (Gr. anomos, irregular ; odous, tooth). An extinct order of 
reptiles, called by Huxley Dicynodontia. 
ANoMURA (Gr. anomos, irregular ; owra, tail). A tribe of Decapod Crus- 
taceans, of which the Hermit-Crabs are the type. 
ANOPLURA (Gr. anoplos, unarmed ; ow/'a, tail). An order of apterous in- 
sects. 
AnourA or ANURA (Gr. a, without ; owra, tail). An order of Amphibia 
Sopra, the Frogs and Toads, in which the adult is destitute of a 
tail, 
ANTENNA (Lat. antenna, a yard-arm). The jointed horns or feelers pos- 
sessed by the majority of the Articulata, 
ANTENNULES (diminutive of antenne). Applied to the smaller pair of 
antennee in the Crustacea. 
ANTHROPOID (Gr. anthropos, man ; eidos, form). Applied to those monkeys 
which make the nearest approach in anatomical structure to man. 
APHANIPTERA (Gr. aphanos, inconspicuous ; pteron, a wing). An order 
of insects comprising the fleas. 
APLACENTAL (Gr. a, without ; Lat. placenta, a cake). Applied to those 
Mammals in which the young is destitute of a placenta (see Placenta). 
APTEROUS (Gr. a, without; pteron, a wing). Destitute of wings. 
Aquatic (Lat. aqua, water). Inhabiting water. 
AQUIFEROUS (Lat. aqua, water; fero, I carry). Applied to the water- 
carrying ¢anal-system of the sponges. 
ARACHNIDA (Gr. arachne, a spider), A class of Articulata, comprising 
spiders, scorpions, and allied animals. 
ARANEIDA (Lat. wranea, a spider), The order of Avachnida comprising 
the true spiders. 
ARCHRHOPTERYX (Gr. archaios, ancient; pterux, a wing). <A fossil bird, 
which alone constitutes the order Saurure. 
ARENACEOUS. Sandy, or composed of grains of sand. 
ARTHROPODA. (Gr. arthros, a joint; podes, feet). Thedivision of Annu- 
losa, in which the body is furnished with jointed appendages. 
ARTICULATA (Lat. articulus, diminutive of artus, a joint). Sometimes 
used in the same sense as the term Arthropoda. — 
ARTIODACTYLA (Gr. artios, even; daktulos, a finger or toe), <A division 
of the hoofed quadrupeds (Ungulata) in which each foot has an even 
number of toes (two or four). 
ASCIDIOIDA (Gr. askos, a bag or a leather bottle; eidos, form). Some- 
times employed to designate the Z'wnicata, an order of the lower Mol- 
