GLOSSARY. 



ABDOMEN (Lat. abdo, I conceal). The posterior cavity of the body, contain- 

 ing the intestines and others of the viscera. In many Invertebrates there 

 is no separation of the body-cavity into thorax and abdomen, and it is only 

 in the higher Annulosa that a distinct abdomen can be said to exist. 



ABEREANT (Lat. aberro, I wander away). Departing from the regular type. 



ABNORMAL (Lat. ab, from ; norma, a rule). Irregular ; deviating from the 

 ordinary standard. 



ABRANCHIATE (Gr. a, without; bragchia, gill). Destitute of gills or bran- 

 chiae. 



ACANTHOPTERYGII (Gr. akantha, spine ; pterux, wing). A group of bony 

 fishes with spinous rays in the front part of the dorsal fin. 



ACARINA (Gr. akari, a mite). A division of the Arachnida, of which the 

 Cheese-mite is the type. 



ACEPHALOUS (Gr. a, without ; kephale, head). Not possessing a distinct 

 head. 



ACETABULA (Lat. acetabulum, a cup). The suckers with which the cephalic 

 processes of many Cephalopoda (Cuttle-fishes) are provided. 



ACETABULUM. The cup-shaped socket of the hip-joint in Vertebrates. 



ACRODONT (Gr. akros, high ; odous^tooih). Applied to Lizards, in which the 

 teeth are anchylosed with the summit of the jaw. 



ACROGENS (Gr. akros, high ; gennao, I produce. ) Plants which increase in 

 height by additions made to the summit of the stem, by the union of the 

 bases of the leaves. 



ACTINOZOA (Gr. aktin, a ray ; and zoon, an animal). That division of the 

 Ccelenterata of which the Sea-anemones may be taken as the type. 



ALVEOLI (Lat. dim. of alvus, belly). Applied to the sockets of the teeth. 



AMBULACRA (Lat. ambulacrum, a place for walking). The perforated spaces 

 or "avenues" through which are protruded the tube-feet, by means of 

 which locomotion is effected in the Echinodermata. 



AMBULATORY (Lat. ambulo, I walk). Formed for walking. Applied to a 

 single limb, or to an entire animal. 



AMMONITID^;. A family of Tetrabranchiate Cephalopods, so called from the 

 resemblance of the shell of the type-genus, Ammonites, to the horns of the 

 Egyptian God, Jupiter- Ammon. 



AMCEBA (Gr. amoibos, changing). A species of Rhizopod, so called from the 

 numerous changes of form which it undergoes. 



AJVKEBIFORM. Resembling an Amoeba in form. 



AMORPHOZOA (Gr. a, without ; morphe, shape ; zoon, animal). A name some- 

 times used to designate the Sponges. 



AMPHIBIA (Gr. amphi, both; bios, life). The Frogs, Newts, and the like, 

 which have gills when young, but can always breathe air directly when 

 adult. 



AMPHICCELOUS (Gr. amphi, at both ends ; koilos, hollow). Applied to verte- 

 brae which are concave at both ends. 



