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

e specialized coördinating apparatus which endows animals with sensation and volition. In vertebrates it is often divided into three systems: the central, brain and spinal cord; the peripheral, cranial and spinal nerves; and the sympathetic. See Brain, Nerve, Spinal cord, under Spinal, and Sympathetic system, under Sym…

on the side with, the neural, or cerebro-spinal, axis; -- 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 segmen…

to both the neuron and the enteron; as, the neurenteric canal, which, in embroys of many vertebrates, connects the medullary tube and the primitive intestine. See Illust. of Ectoderm.

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

The deep-seated parts of the vertebrate skeleton which are relation with the nervous axis and locomation. Owen.

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

An elastic cartilagelike rod which is developed beneath the medullary groove in the vertebrate embryo, and constitutes the primitive axial skeleton around which the centra of the vertebræ and the posterior part of the base of the skull are developed; the chorda dorsalis. See Illust. of Ectoderm.

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.…

nd surrounds the great foramen by which the spinal cord leaves the cranium. In the higher vertebrates it is usually composed of four bones, which become consolidated in the adult. -- Occipital point (Anat.), the point of the occiput in the mesial plane farthest from the ophryon.

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

A group of Mesozoic birds having the jaws armed with teeth, as in most other vertebrates. They have been divided into three orders: Odontolcæ, Odontotormæ, and Saururæ.

olfactory nerves; the olfactory cells. Olfactory organ (Anat.), an organ for smelling. In vertebrates the olfactory organs are more or less complicated sacs, situated in the front part of the head and lined with epithelium innervated by the olfactory (or first cranial) nerves, and sensitive to odoriferous particles con…

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

A metamere of the vertebrate skeleton; an osteomere; a vertebra. Owen.

The science which treats of the bones of the vertebrate skeleton.

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.

the small bones or particles of calcareous or other 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.

An extinct genus of huge vertebrates, probably dinosaurs, known only from four-toed tracks in Triassic sandstones.

An artifical division of vertebrates, including those that lay eggs; -opposed to Vivipara.