Cephalic Sentence Examples
Within the velar area the eyes and the cephalic tentacles commence to rise up, and on the surface of the post-oral region is formed a cap-like shell and an encircling ridge, which gradually increases in prominence and becomes the freely depending mantle-skirt.
Curiously enough, however, they differ from the cephalic Molluscan eye in the fact that, as in the vertebrate eye, the filaments of the optic nerve penetrate the retina, and are connected with the re surfaces of the nerve-end cells nearer the lens instead of with the opposite end.
A fact of special interest in regard to them is that the genus Poliochera, from the Coal Measures, appears to be a member of the same group. The name Cryptostemma, given to the first-known genus of the order, described by Guerin-Meneville, refers to the supposed concealment of the eyes by the movable cephalic sclerite.
Another form, Rhopalophorus, has two cephalic tentacles that are retractile and covered with hooks.
In the regions of greatest linguistic mixture is the greatest heterogeneity of cephalic index.
The next, the copepodid or cyclopid, stage is characterized by a cylindrical segmented body, with foreand hind-body distinct, and by having at most six cephalic limbs and two pairs of swimming feet.
In Paradoxides, for example, there are about twenty freely movable segments followed by a very short and small pygidium, whereas in Agnostus the freely movable segments are reduced to two and the pygidium is as large as the cephalic shield.
They are also well marked on the cephalic shield, the tergal elements being represented by a median axial elevated area showing indistinct signs of segmentation, and a lateral unsegmented plate, the gena, which carries the eyes.
From the cephalic part of this primary diverticulum solid rods of cells called the hepatic cylinders grow out, and these branch again and again until a cellular network is formed surrounding and breaking up the umbilical and vitelline veins.
In some Lamellibranchs (Pecten, Spondylus, Pholas, Mactra, Tellina, Pectunculus, Galeomma, &c.), although cephalic eyes are generally absent, special eyes are developed on the free margin of the mantle-skirt, apparently by the modification of tentacles commonly found there.
AdvertisementThey are totally distinct from the cephalic eyes of typical Mollusca, and have a different structure and historical development.
Rudimentary cephalic eyes occur in the Mytilidae and in Avicula at the base of the first filament of the inner gill, each consisting of a I pigmented epithelial fossa containing a cuticular lens.
Just behind the ciliated ring is a pair of larval eyes which disappear in the adult; these correspond to the cephalic eyes of Lamellibranchs.
Even in external view, careful inspection will show that the body is divisible into four regions, namely, cephalic, atrial, abdominal and caudal.
The cephalic region includes the rostrum or praeoral [[Right Fig]].
AdvertisementFor practical purposes, however, it is convenient to include the two following somites also as cephalic.
A remarkable feature found only in the Stomatopoda is the reappearance of segmentation in the anterior part of the cephalic region.
The mesoblast of the cephalic (naupliar) region probably arises in connexion with the lips of the blastopore and consists of loosely-connected cells or mesenchyme.
All the cephalic appendages are much reduced, the mandibles have no palps, and the maxillulae are vestigial.
At the base of the head dorsally are a pair of flat tentacular lobes from the edges of which the cephalic filaments or captacula arise.
AdvertisementIt was conceived by Huxley, among others, that the same number of cephalic somites would be found to be characteristic of all the diverse classes of Arthropoda, and that the somites, not only of the head but of the various regions of the body, could be closely compared in their numerical sequence in classes so distinct as the Hexapods, Crustaceans and Arachnids.
But in higher Crustacea the cephalic " tagma " is extended, and more somites are added to the fusion, and their appendages adapted as jaws of a kind.
This gives seven somites to the Hexapod's head, the tergites of which are fused to form a cephalic carapace or box.
Linguistically the Lapps belong to the Finno-Ugrian group (q.v.); the similarity of their speech to Finnish is evident though 2 Bertillon found in one instance a cephalic index of 94.
Shell with very low spire, without umbilicus, internal partitions frequently absorbed; a single ctenidium; a cephalic penis present.
AdvertisementShell depressed, with rounded aperture; cephalic tentacles long.
Cephalic shield broad, thick and simple; shell wholly internal, thin, spire much reduced, aperture very large.
During an external cephalic version (also known as version), the obstetrician attempts to turn the fetus to a head first position before labor begins by manipulating the outside of the abdomen.
External cephalic version-Manual manipulation of the abdomen in order to turn a breech baby; also known as version.
In the Orthorrhapha, in the pupae of which the appendages of the perfect insect are usually visible, the pupa-case generally splits in a straight line down the back near the cephalic end; in front of this longitudinal cleft there may be a small transverse one, the two together forming a T-shaped fissure.
Below the surface these walls are excavated with blood-vessels, so that the sac is practically a series of blood-vessels covered with renal epithelium, and forming 6 Cephalic tentacle.
The head is seen in front resting on the foot and carrying a median non-retractile snout or rostrum, and a pair of cephalic tentacles at the base of each of which is an eye.
The Heteropoda are further remarkable for the high development of their cephalic eyes, and for the typical character of their osphradium (Spengel's olfactory organ).
Shell flattened; no cephalic tentacles.
Shell spiral; four cephalic tentacles; eyes absent; two pedal appendages.
The detorted visceral commissure shows a tendency to the concentration of all its elements round the oesophagus, so that except in the Bullomorpha and in Aplysia the whole nervous system is aggregated in the cephalic region, either dorsally or ventrally.
It carries two pairs of cephalic tentacles and a pair of sessile eyes.
Posterior cephalic tentacle; and b, the eyes.
Cephalic shield short, truncated posteriorly; eyes deeply embedded; three calcareous stomachal plates; shell external, with reduced spire.
Cephalic shield continuous with neck; twelve to fourteen stomachal plates; a posterior pallial filament passing through a notch in shell.
Cephalic shield ending posteriorly in a median point; shell internal, largely membranous; no radula or stomachal plates.
Cephalic shield pointed behind; shell internal, chiefly membranous, with calcified nucleus, nautiloid; parapodia forming fins.
Cephalic shield continuous with dorsal integument; no shell; ctenidium projecting from mantle cavity.
Karl Semper has shown that these slugs have, in addition to the usual pair of cephalic eyes, a number of eyes developed upon the dorsal integument.
Hickson and others, that in the bivalves Pecten and Spondylus, which also have eyes upon the mantle quite distinct from typical cephalic eyes, there is the same relationship as in Oncidiidae of the optic nerve to the retinal cells.
The brain innervates the eyes and feelers, and must be regarded as a " syncerebrum " representing the ganglia of the three foremost limb-bearing somites united with the primitive cephalic lobes.
The development of these organs, which in the Protonemertine are but grooves in the epidermis, not far removed from the similar cephalic slits of many Turbellaria, reaches its height in Drepanophorus.
They are the head slits cephalic fissures, " Kopfspalten ") so characteristic of this subdivision (figs.
That any partial fusion of originally distinct chitinous plates takes place in the cephalic shield of Trilobites, comparable to the partial fusion of bony pieces by suture in Vertebrata, is a suggestion contrary to fact.
Four pairs of appendages besides these are seen to belong to the cephalic tergum.