zoo 
Z YG 
arms the appearance of an imperfect flower. 
The last order, Infusoria, is scarcely distin- 
guished from the Intestina and Mollusca by 
any other character than the minuteness of 
the individuals belonging to it, and their 
spontaneous appearance in animal and ve- 
getable infusions, where we can discover no 
traces of the manner in which they are pro- 
duced. The process, by which their num- 
bers are somethnes increased, . is no less as- 
tonishing than their first production ; for 
several of the genera often appear to di- 
vide spontaneously, into two or more parts, 
which become new and distinct animals, so 
that in such a case the question respecting 
the identity of an individual would be very 
difficult to determine. The volvox, and 
some of the vorticell® are remarkable for 
their continual rotatory motion, probably 
intended for the purpose of straining their 
food out of the water: while some other 
species of the vorticellae resemble fungi or 
corallines in miniature. 
ZOOPHYTA, in natural histor3', an 
order of the class Vermes. Zoophyta are 
composite animals, holding a medium be- 
tween animals and vegetables. Most of 
them take root and grow up into stems, 
multiplying life in their branches and deci- 
duous buds, and in the transformation of 
their animated blossoms or polypes, which 
are endowed with spontaneous motion. 
Plants, therefore, resemble zoophyta, but 
are destitute of animation and the power 
of loco-motion ; and zoophyta are, as it 
were, plants, but furnished with sensation 
and the organs of spontaneous motion. 
Of these some are soft and naked, and 
ethers are covered with a hard shell : the 
former are by some naturalists called zoo- 
phytes, and the latter are denominated 
lithophytes. There are fifteen genera, viz. 
Alcyoniura 
Antiputhes 
Cellepora 
Corallina 
Fiustra 
Gorgonia 
Hydra 
Isis 
Madrepora 
Millepora 
Pennatula 
Sertularia 
Spongia 
Tubipora 
Tubularia. 
The coral reefs that surround many 
islands, particularly those in the Indian 
Archipelago, and round New Holland, are 
formed by various tribes of these animals 
particularly by the Cellepora, Isis, Madre- 
pora, Millepora, and Tubipora. The ani- 
mals form these corals with such rapidity, 
that enormous masses of them very speedily 
appear where there were scarcely any marks 
of such reefs before. 
ZOSTERA, in botany, a genus of the 
Monandria Monogynia class and order. 
Natural order of Inundafre. Aroidese, Jus- 
sieu. Essential character : spadix, linear, 
within the sheath of the leaves, flower bear- 
ing on one side ; calyx none ; corolla none ; 
anther sessile, opposite to the germ stig- 
mas two, linear; capsule one-seeded. There 
is but one species, viz, Z. marina, grass- 
wrack, and many varieties. 
ZWINGERA, in botany, so named from 
Theodoras Zwinger, Professor of Anatomy 
and Botany at Basil, a genus of the De- 
candria Monogynia class and order. Na- 
tural order of Terebintaceae, Jussieu. Es- 
sential character : calyx five-parted ; petals 
five; filaments widened at the base, hairy; 
capsule five, coriaceous, one-seeded, in- 
serted into a fleshy receptacle. There is 
but one species, viz. Z. amara, a native of 
the woods of Guiana. 
ZYGIA, in natural history, a genus ^of 
insects of the order Coleoptera : anten- 
naj raoniliforra ; feelers equal, filiform ; lip 
elongated, membranaceous ; jaw one-tdoth- 
ed. There is only one species, viz. Z. ob- 
longa, which is found in the East. 
ZYGOPHYLLUM, in botany, lean, 
caper, a genus of the Decandria Monogynia 
class and order. Natural order of Grui- 
nales. Rutaceae, Jussieu. Essential cha- 
racter: calyx five-leaved ; pfetalsfive; nec- 
tary ten-leaved, covering the germ, and 
bearing the stamens; capsule five-celled. 
There are fourteen species; of these the 
following may be noticed : Z. fostidum, fetid 
bean-caper : the leaves of this plant stand 
on long footstalks, and diffuse widely a 
strong foxy smell : it flowers from July to 
September. The fruiting peduncle turns 
back, whence its trivial name retrofractum. 
It is a native of the Cape of Good Hope. 
Z. morgsana, four-leaved bean-caper : has 
a shrubby stem, divided into many irre- 
gular-jointed branches, rising four or six 
feet high ; leaves t.hick and succulent, and 
placed by fours at each joint, two on each 
side the stalk opposite ; the fruit has four 
membranaceous wings, resembling the sails 
of a mill. Z. arboreum, tree bean-caper, 
is a very handsome tree, forty feet high, 
with a very large, thick, elegant head ; 
trunk upright, dividing into numerous op- 
posite branches ; flowers inodorous, large, 
handsome, which give the tree a most beau- 
tiful appearance when in bloom. 
