GLOSSARY. 
Ab-do'men. In mammals the part 
of the trunk below or behind 
the thorax; in insects the third 
region of the body, or hind 
body. 
Ab ER RANT. Departing from the 
regular or normal type. 
Ab-o'ral. Opposite the oral or 
mouth region. 
A-bran'chi-ate (Gr. a, without; 
bragchia, gills). Without bran- 
chiae or gills. 
A-cu'mi-nate. Ending in a pro- 
longed point. 
Al-ve'o-lus. a cavity forming 
the socket in the jaws of verte- 
brates for the teeth. 
Am-bu-la'crum (Lat. from ambu- 
lave, to walk, a garden- walk). 
The perforated space or area 
in the shell of the sea-urchin or 
the arm of a star- fish, through 
which the foot-tubes or ambu- 
lacral feet are protruded. 
A-me-ta'bo-lic (Gr. a, without ; 
metahole, change). Referring 
to insects and other animals 
which do not undergo a meta- 
morphosis. 
A-mor'phous (Gr. or, without; 
morplie, form). Without a defi- 
nite figure ; shapeless ; espe- 
cially applicable to sponges. 
Am-phi-C(e'lous (Gr. amphi ; 
koilos, hollow). Applied to 
vertebrae which are doubly 
concave, or hollow at both 
ends. 
A-nal'o-gy (Gr. analogia, propor- 
tion). The relation between 
organs which differ in struc- 
ture, but have a similar func- 
tion; as the wings of insects 
and birds. 
A-NAS-TO-MO^siNG. Inosculatiug 
or running into each other like 
veins. 
An-chy-lo'sis. The growing to- 
gether of two bones so as to 
prevent motion between them. 
An'nu-late. When a leg or an- 
tenna is surrounded by narrow 
rings of a different color. 
A'pla-ckn-tal. Referring to 
tliobc mammals in which the 
embryos are destitute of a pla- 
centa. 
A'po Dous. Footless. 
Ap'te ROUS (Gr. a, without; p^^r- 
on, wing). Destitute of wings. 
A-qui'fe ROUS (Lat. aqua, water; 
fero, I carry). Applied to the 
water-carrying or water-vascu- 
lar system of the sponges, etc. 
A-rach'ni-da (Gr. aracline. a spi- 
der). The class of Arthropods, 
