366 GLOSSARY. 
TUBULARIDA (Lat. tuba, atube), Often used instead of Corynida to desig- 
nate an order of the Hydrozoa. 
TUNICATA (Lat. ¢unica, a cloak), The Sea- pete a class of the Mollus- 
coida. 
Una (Gr. olené, the elbow). The outermost of the two bones of the 
fore-arm, corr esponding with the fibula of the hind-limb. 
UMBO (Lat. the boss of a shield). The beak of a bivalve shell. 
UMBRELLA. The contractile disc of one of the Lucernarida. 
UNGULATA (Lat. ungula, a hoof), The order of Mammalia comprising the 
Hoofed Quadrupeds. 
UNIVALVE (Lat. wnus, one; valve, folding-doors). Applied to shells 
composed of a single piece or valve. 
URODELA (Gr. oura, tail; delos, visible). The order of the ‘‘tailed” 
Amphibians, 
VACUOLES (Lat. vacuus, empty). The little cavities formed in the in- 
terior of many of the Protozoa by the presence of particles of food 
surrounded by a little water. 
VENTRAL (Lat. venter, the stomach), Relating to the inferior surface of 
the body. 
VENTRICLE (Lat. ventriculus, diminutive of venter, belly). One of the 
cavities of the heart. 
VERMES (Lat. vermis, a worm). Sometimes used at the present day in the 
same, or nearly the same, sense as Annuloida, or as Annuloida plus 
the Anarthropoda. 
VERMIFORM. Worm-like in shape. 
VERTEBRA (Lat. verto, turn). One of the bones composing the spinal 
column or back-bone. 
VERTEBRATA The sub-kingdom comprising animals, almost all of which 
. have a more or less well developed vertebral column. 
VESICLE (Lat. vesica, a bladder). A little sac, bladder, or cyst. 
VISCERA (Lat. viscus). The internal organs of the body. 
VIVIPAROUS (Lat. vivus, alive ; and pario, I bring forth). Applied to 
animals which bring forth their young alive. 
XIPHOSURA (Gr. xiphos, a sword; oura, tail). An order of Crustacea, 
comprising the King-Crabs. 
ZoOip (Gr. zodn, animal ; eidos, form), The more or less completely in- 
dependent organisms produced from a primitive being by gemmation 
or fission, whether these remain attached to one another or are 
detached and set free. 
ZOOPHYTE (Gr. zodn, animal; phuton, plant). Loosely applied to many 
plant-like animals, such as Sponges, Corals, Sea-anemones, Sea-firs 
Sea-mats, &c. 
