362 GLOSSARY. 



Amphidiscs (Ctr. amphi, at botli ends ; disleos, a qnoit or round plate). The 



spicules wliicli surround the reproductive "geuiiuules" of Sjoomjilla, and 



resemble two toothed wheels united by an axle. 

 Amphioxus (Gr. amphi, at both ends ; oxu^, sharp). The Lancelet, a curious 



little fish, which alone constitutes the order Pharyngobranchii. 

 Amphipoda (Gr. amphi; and podes, feet). An order of the Crustacea, so 



called because some of the feet are directed forwards and some backwards. 

 Analogous. Applied to parts which perform the same function. 

 AsAETHROPODA (Gr. a, without ; arthros, a joint ; podes, feet). The division 



of Aniiidose animals in which there are no articulated appendages. 

 ANN'iiLIDA (a Gallicised form of Annulaki, Lat. annuttis, a ring). The Ringed 



Worms, which form one of the divisions of the Anarthropoda. 

 A>.-NULOSA (Lat. annulus, a ring). The sub-kingdom comprising the Scoleeida, 



Anarthropoda, and the Arlhropoda or Articiilaia, in all of which the body 



is more or less evidently composed of a succession of rings. 

 Anomodontia (Gr, anonios, irregular ; odous, tooth). An extinct order of 



Reptiles, called by Huxley IHcynodoutiit. 

 Ano.mura (Gr. anomos, irregular ; oura, tail). A tribe of Decapod Crustaceans, 



of which the Hermit-crabs are the type. 

 Anoplura (Gr. anoplos, unarmed ; onra, tail). An order of Apterous Insects. 

 Asoura or Anuea (Gr. a, without ; oura, tail). An order of Amphibia, 



comprising the Frogs and Toads, in which the adult is destitute of a 



tail. 

 Antenn.e (Lat. antenna, a yard-arm). The jointed horns or feelers possessed 



by tlie majority of tlie Articulaia. 

 Antennules (diminutive of antennm). Applied to the smaller pair of antenna 



in the Crustacea. 

 Anthropoid (Gr. anihropos, man; eidos, form). Applied to those Monkeys 



which make the nearest approach in anatomical structure to Man. 

 Aphaniptera (Gr. aphanos, inconspicuous; ^^ero?;, a wing). An order of 



Insects comprising the Fleas. 

 Aplacental (Gr. a, without ; Lat. placenta, a cake). Applied to those Mam- 

 mals 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. aqxia, water; /ero, I carry). Applied to tlie water-carrying 



canal-system of the Sponges. 

 Arachnida (Gr. arachne, a spider). A class of Articutato, comprising Spiders, 



Scorpions, and allied animals. 

 Araneid.^ (Lat. aranea, a spider). The order of Arachnida, comprising the 



true Spiders. 

 ABOH.EOPTERYX (Gr. archcdos, ancient ; pterux, wing). A fossil bird, which 



alone constitutes the order Saururee. 

 ArenaC'E(jus. Sandy, or composed of grains of sand. 

 Arthropoda (Gr. arthros, a joint ; podes, feet). The division of Annulosa, 



in which the body is furnished with jointed appendages. 

 Articulata (Lat. articulus, dinunutive of artus, a joint). Sometimes used in 



the same sense as the term Artliropoda. 

 Artiodactyla (Gr. artios, even ; duklidns, a finger or toe). A division of the 



hoofed quadrupeds ( UngulaCa) in which each foot has an even number of 



toes (two or four). 

 AsciDIOIDA ((Jr. askos, a bag or a leather bottle ; eidos, form). Sometimes 



employed to designate the Tunicata, an order of the lower Mollusca, from 



the resemblance of the body in many cases to a two-necked jar. 

 Asexual. Applied to modes of reproduction in which the sexes are not con- 

 cerned (e.g., gemmation and fission). 

 Asteroidea (Gr. aster, a star ; and eidos, form). An order of Echmodermataj 



comprising the Star-fishes, characterised by their rayed form. 

 AsTOMATOUS (Gr. a, ■without ; stoma, mouth). Not possessing a mouth. 

 Atriu.m (Lat. a hall). Applied to the large chamber or "cloaca," into which 



the intestine opens in the Tunicata. 



