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Having six-rayed spicules; belonging to the Hexactinellinæ.

Belonging to the Hexactinellinæ, a group of sponges, having six-rayed siliceous spicules.

An order of vitreous sponges, having glassy six-rayed, siliceous spicules; -- called also Hexactinellinæ.

See Picul.

Having a small, distinct point; apiculate. Henslow.

der of rhizopods, usually having a siliceous skeleton, or shell, and sometimes radiating spicules. The pseudopodia project from the body like rays. It includes the polycystines. See Polycystina.

bulacra on the upper side of the spatangoid and clypeastroid sea urchins. See Illust. of Spicule, and Sand dollar, under Sand.

Having the parts spreading out like a wheel; wheel-shaped; as, a rotate spicule or scale; a rotate corolla, i.e., a monopetalous corolla with a flattish border, and no tube or a very short one.

Having a straight shaft with whorls of spines; -- said of certain sponge spicules. See Illust. under Spicule.

A hard chitinous or calcareous process or corpuscle, especially a spicule of the Alcyonaria.

Having six rays; -- said of certain sponge spicules. See Illust. of Spicule.

fera, which includes those that have the skeleton composed mainly of siliceous fibers or spicules.

Having spines arranged spirally. See Spicule.

One of the microsporic siliceous spicules which occur abundantly in the texture of sponges, and are sometimes found fossil, as in flints.

lied genera. These sponges have a fine and compact texture, and contain minute siliceous spicules.

See Picul.

A division of Spongiæ in which the spicules are siliceous and have four branches diverging at right angles. Called also Tetractinellinæ.

Having four branches diverging at right angles; -- said of certain spicules of sponges.

A delicate, hairlike siliceous spicule, found in certain sponges. Trichite sheaf (Zoöl.), one of the small sheaflike fascicles of slender setæ characteristic of certain sponges. See Illust. under Spicule.

Curved in three directions; as, a tricurvate spicule (see Illust. of Spicule).