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A receptacle, or pouch, connected with the oviducts of many invertebrates in which the eggs are retained until they hatch or until the embryos develop more or less. See Illust. of Hermaphrodite in Append.

The terminal part of the oviduct in insects and various other invertebrates. See Illust., of Spermatheca.

ater vascular system (Zoöl.), a system of vessels in annelids, nemerteans, and many other invertebrates, containing a circulating fluid analogous to blood, but not of the same composition. In annelids the fluid which they contain is usually red, but in some it is green, in others yellow, or whitish.…

The anal opening of certain invertebrates and fishes; also, the external cloacal opening of reptiles, birds, amphibians, and many fishes.

The orifice of the oviduct of an insect or other invertebrate.

A pore by which the water tubes of various invertebrates open externally.

One of a system of tubular excretory organs having external openings, found in many invertebrates. They are believed to be analogous in function to the kidneys of vertebrates. See Illust. under Trematodea, and Sporocyst.

pintail. (b) The old squaw. -- Winter egg (Zoöl.), an egg produced in the autumn by many invertebrates, and destined to survive the winter. Such eggs usually differ from the summer eggs in having a thicker shell, and often in being enveloped in a protective case. They sometimes develop in a manner different from that…

pecial organ which secretes the yolk of the eggs in many turbellarians, and in some other invertebrates. See Illust. of Hermaphrodite in Appendix. -- Yolk sack (Anat.), the umbilical vesicle. See under Unbilical.

all green granulelike bodies found in the interior of certain stentors, hydras, and other invertebrates.

Any one of numerous species of invertebrate animals which more or less resemble plants in appearance, or mode of growth, as the corals, gorgonians, sea anemones, hydroids, bryozoans, sponges, etc., especially any of those that form compound colonies having a branched or treelike form, as many corals and hydroids.…