G L S S A E Y. 



Abdomex (Lat. ahdo, I conceal). The posterior cavity of tlie 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. 

 Aberrant (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 brau- 



chise. 

 Acanthopterygii (Gr. akantha, spine ; ptarux, wing). A group of bony 



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

 Agarina (Gr. akari, a mite). A division of the AracJmida, of which the 



Cheese-mite is the type. 

 Acephalous (Gr. a, without ; kcjjJiale, head). Not possessing a distinct 



head. 

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



processes of many Ccjjhalo^Joda (Cuttle-fishes) are provided. 

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

 AcRODONT (Gr. akros, high ; odous, tooth). Applied to Lizards, in which the 



teeth are anchylosed with the summit of the jaw. 

 AcroCtENS (Gr. akros, high; gcnnao, 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 alvtis, belly). Applied to the sockets of the teeth. 

 Ambul.A-CRA (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 Echmodcrinatcc. 

 Ambulatory (Lat. amhulo, I walk). Formed for walking. Applied to a 



single limb, or to an entire animal. 

 Ammonitid^e. a family of Tetrabranchiate Cephalopods, so called from the 



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



Egyptian god, Jupiter- Ammon. 



