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ar layer which lies beneath the chitinous cuticle of arthropods, annelids, and some other invertebrates.

ny small crustacean. In a wider sense, the word is often loosely applied to various small invertebrates.

Same as Invertebrate.

orny animal substance entering into the composition of the skeleton of sponges, and other invertebrates; -- called also keratode.

aining small, calcareous concretions (otoliths). They are found in many Medusæ, and other invertebrates, and are supposed to be auditory organs.

The middle body layer in some invertebrates.

ed with hemoglobin in the muscle tissue of a large number of animals, both vertebrate and invertebrate.

opposed to hemal. As applied to vertebrates, neural is the same as dorsal; as applied to invertebrates it is usually the same as ventral. Cf. Hemal. Neural arch (Anat.), the cartilaginous or bony arch on the dorsal side of the centrum of the vertebra in a segment of the spinal skeleton, usually inclosing a segment of…

Having the limbs on, or directed toward, the neural side, as in most invertebrates; -- opposed to Ant: hæmapodous. G. Rolleston.

An embryo or certain invertebrates in the stage when the primitive band is first developed.

An oarlike swimming organ of various invertebrates. Oar cock (Zoöl), the water rail. [Prov. Eng.] -- Spoon oar, an oar having the blade so curved as to afford a better hold upon the water in rowing. -- To boat the oars, to cease rowing, and lay the oars in the boat. -- To feather the oars. See under Feather., v. t.…

A little eye; a minute simple eye found in many invertebrates.

One of the single eyes forming the compound eyes of crustaceans, insects, and other invertebrates.

An auditory cyst or vesicle; one of the simple auditory organs of many invertebrates, containing a fluid and otoliths; also, the embryonic vesicle from which the parts of the internal ear of vertebrates are developed.

her hard substance in the internal ear of vertebrates, and in the auditory organs of many invertebrates; an ear stone. Collectively, the otoliths are called ear sand and otoconite.

The entire covering of an invertebrate animal, as echinoderm or coelenterate; the integument.

The membrane surrounding the mouth of an invertebrate animal.

A group of invertebrates including the Tunicata and Enteropneusta. -- Pha*ryn`gop*neus"tal, a.

A chitinous structure which supports the gill in some invertebrates.

or forming, the front of the head. Procephalic lobe (Zoöl.), that part of the head of an invertebrate animal which is in front of the mouth.