Praeoral Sentence Examples

Praeoral ciliated ring, or prototroch.

The larva swims by a ri ig of cilia, which corresponds with the praeoral circlet of a Trochosphere.

In the centre of the praeoral lobe is a tuft of cilia.

A recently described species, Dolichorhynchus indicus, characterized by the great length of the praeoral lobe or snout, has been dredged in the Indian Ocean.

The cephalic region includes the rostrum or praeoral [[Right Fig]].

There are two pairs of specialized cerebral nerves innervating the praeoral lobe, and provided with peripheral ganglia placed near the termination of the smaller branches.

This becomes divided into two, the right half forming the cavity of the rostrum, while the left acquires an opening to the exterior, and forms the praeoral pit of the larva, which subsequently gives rise to special ciliated tracts in the vestibule of the mouth mentioned above.

The mouth (o) is in front of the tentacles, on the ventral side, and is overhung by a mobile praeoral hood, in which is the principal part of the nervous system.

Even if it be admitted that the postseptal space may be the metasomatic cavity, the praeseptal space can hardly be regarded as coelomic in nature, since it is in continuity with the vascular system; while Masterman's conclusion that the cavity of the praeoral hood (the supposed proboscis-cavity) is separated from that of the supposed collar has received no confirmation.

The epistome of the adult Phoronis cannot well be the proboscis since its cavity is continuous with the lophophoral coelom, and because the praeoral hood of Actinotrocha is entirely lost at the metamorphosis.

Since the proboscis is a purely larval organ in this genus, it may be supposed that the coelomic space which properly belongs to it fails to develop, but that the praeoral hood itself is none the less the morphological representative of the proboscis.

The first to appear are the antennae, into which the praeoral somites are prolonged.

They form the somites of the praeoral lobes.

The praeoral somite develops the rudiment of a nephridium, but eventually entirely disappears.