160 ZOOLOGY. 



V Amphiccelus (Gr. amphi, both ; koilos, hollow) A term applied to 



double-concave vertebral. 

 u Amphioxus (Gr. amphi, both ; oxus, sharp) A little fish (the 



lancelet) which tapers at both ends. 

 Anarthropoda (Gr. a, without ; arthros, a joint ; pous, a foot) A 



division of Annulosa, so called because they are destitute of 



jointed limbs. 

 I Anchylosis (Gr. ankulos, crooked) The union of two bones which 



are immovably united together. 



Animalcule (diminutive of animal) The popular name for a micro- 

 scopic animal. 



Annelida (Lat. annulos, a ring) A class of Anarthropoda, em- 

 bracing the earth-worm and the leech, &c. 

 Annuloida (Lat. annulus, a ring) A sub-kingdom, including the 



Eclunodermata and Scolecida. 

 Annulosa (Lat. annulus, a ring) A sub-kingdom, composed of the 



Arthropoda and Anarthropoda. Formerly called Articulata. 

 Antenna (Lat. antenna, the yard of a ship) The jointed 



appendages of the head in Insecta, Crustacea, and Myria- 



poda. 

 Antennules (diminutive of antennae) The shorter pair of an- 



tennse in the Crustacea. 



Arachnida (Gr. arachne, a spider) A class of Artltropoda, in- 

 cluding spiders, scorpions, and mites. 

 Archseopteryx (Gr. archaios, ancient ; pleryx, a wing) An extinct 



bird found in the oolitic rocks; the only representative of 



the order Saururce of Huxley. 

 Ascidioida (Gr. askos, a bag) A class of Molluscoida, so called 



because they resemble in shape a two-necked bottle. This 



class is also termed Tunlcata. 

 iXktlas (Gr. Atlas, the god that holds up the earth) The vertebra 



which supports the skull, 

 tx Atrium (a hall) Applied to the cavity in the Tunlcata into 



which the intestine opens. 

 (/ Auricle (diminutive of auris, an ear) One of the cavities of the 



heart which receives blood, and transmits it to the ventricle. 

 j/Autophagi (Gr. autos, self; phago, I eat) A term applied to 



those birds which are able to run about, and obtain food as 



soon as they leave the shell. 



Aves (Lat. avis, a bird) One of the classes of Vertebra-la. 

 Avicularium (Lat. avlcida, a little bird) An appendage of the 



Polyzoa, resembling the head of a bird. 



Belemnites (Gr. belemnos, a dart) An extinct group of Cephalo- 

 poda, allied to the cuttle-fishes. 



Bilateral (Lat. bis, twice; latus, a side) Having two similar 

 sides. 



