In this way very long unsegmentedthreads are produced.
The spread of segmentation through tissues normally unsegmented is very clearly exemplified in the skates' jaws shown in Fig.
Whatever the cause the condition shows how easily a normally unsegmented structure may be converted into a series of repeated parts.
Pro' leg#, an unsegmented appendage found in the larvae of some insects.
Mollusca, a branch of the animal kingdom including those animals with soft, unsegmented bodies, inclosed in two folds of skin known as the mantle.
This ventral nephrocoelic part is divisible in the trunk into a segmented part, which forms the excretory organs proper, and an unsegmented part, the metacoele or true body-cavity of the vertebrate.
Further, according to van Wijhe, the dorsal part of the unsegmented metacoelom is itself segmented, but not, as in the case of the mesocoele, with respect to both splanchnopleuric and somatopleuric walls.
But in all segmented animals the only unsegmented tube which extends the whole length of the body, from mouth to anus, is invariably the gut.
He recognizes in Squalus acanthias, in front of the spino-occipital region, fourteen pairs of such encephalomeres and a median unsegmented termination, which may represent one more pair fused in the middle line, making at least fifteen.
Still more suggestive is it to find that the tube so formed has no appearance whatever of segmentation; it is as unsegmented as the rest of the gut, although, as is seen in Fig.
Hatschek describes in Amphioxus how the coelom splits into a dorsal segmented portion, the protovertebra, and a ventral unsegmented portion, the lateral plates.
Any one of them might be the unsegmentedgut of the segmented animal.
He terms the whole coelomic cavity the procoelom, which is divisible into a ventral unsegmented part, the body-cavity or metacoelom, and a dorsal segmented part, the somite.
These animals have an unsegmented bilateral body, with most of the organs and parts paired, but not repeated longitudinally.
The blood is colorless; the brain, renal organs, and limbs are wanting, and the backbone is represented only by a simple, unsegmented notochord.
In a Phyllopod such as Apus the limbs of the trunk consist of a flattened, unsegmented or obscurely segmented axis or corm having a series of lobes or processes known as endites and exites on its inner and outer margins respectively.
This cenogenetic process is so old that the cavity seems to be unsegmented from the first in all the craniotes, and the rudiment of the gonads also is almost always unsegmented.
The chief and oldest organ of the vertebrate hyposoma, the alimentary canal, is generally described as an unsegmented organ.
The outer skin (epidermis) is unsegmented from the first, and proceeds from the continuous horny plate.
The next change results in the complete separation of the vertebral portion of the plate from the lateral portion; thereby the upper segmented part of the body cavity becomes isolated, and separated from the lower and unsegmented part.
The mesoblast at the base of the brain is more bulky, and there is still a mass of unsegmented mesoblast which forms the tail swellings.
The somites following the second are formed in the regular manner, from before backwards, out of the unsegmented posterior part of the embryo, which rapidly grows in length to supply the necessary material (fig.
The number of the muscle-plates has again increased, but there is still a region of unsegmented mesoblast in the tail.
The somites are first formed in the neck, and are added successively behind in the unsegmented posterior region of the embryo.
The layer with these cells soon increases in thickness, and forms a continuous unsegmented tube of fibrous tissue with flattened concentrically arranged nuclei (fig.
The carapace of the prosoma was unsegmented and often bore a pair of eyes.
The unsegmented dense chitinous sternal plate of the metasoma (XIII to XVIII) is not removed.
Limulus, but are represented by the unsegmented prae-anal region.
Section through an early embryo of Limulus longispina, showing seven transverse divisions in the region of the unsegmented anterior carapace.
A) an oval unsegmented body with three pairs of appendages springing from the ventral surface.
This type is also widely distributed amongst the unsegmented (Gephyrea, Turbellaria), as well as the segmented Vermes, and is typical for the Rotifera.
If this view is correct the larva is to be compared to anunsegmented Chaetopod larva.
The still unsegmented tail has become very prominent and makes an angle of 180 deg.
The larvae of Nerine and Spio, already quoted as examples of an unsegmented arrangement of the ventral ciliated half rings, are both amphitrochal forms.
It becomes divided into numerous segments, which continue to be formed successively from the posterior unsegmented part.
The thorax is unsegmented and indeed almost unrepresented, but the abdomen is long and divided into distinct segments.
Nauplius with only three pairs of appendages, the two hinder biramous, and an unsegmented body.
The body is divided into three regions, an anterior unsegmented region to which are attached two pairs of antennae, mandibles, and maxillae (two pairs).
The tail is applied to the ventral surface of the trunk, and on the latter two pairs of stump-like unsegmented appendages arise, each provided with a pair of claws.
The ventral cord is, as has been stated, at firstunsegmented (fig.
It is tempting to suppose that the long provisional bristles springing from the oral region are the setiform appendages handed down from the unsegmented ancestors of the existing Chaetopod forms.
These nurses possess the form-value of a simple, unsegmented worm-individual.
There were also in the fluid itself a number of medium-size, unsegmented Bacteria, whose movements were somewhat languid.
The nauplius, unlike the larvae which we have been considering, has an unsegmented body, and has only three pairs of limbs.
It has a soft, unsegmented body about half an inch long, provided with numerous blunt lobes which give it a very irregular shape.
Thus the chief advantage in organisation by which the earliest Vertebrates took precedence of the unsegmented Chordonia consisted in the development of internal segmentation.
Undoubtedly both the Tunicates and Acrania have inherited the chorda from a common unsegmented stem-form; and these ancient, long-extinct ancestors of all the chordonia are our hypothetical Prochordonia.
The chorda is completely retained, and surrounded by an unsegmented sheath.
The unsegmented chorda develops between the dorsal medullary tube and the ventral gut-tube.
But thisunsegmented primary axial skeleton is soon replaced by the segmented secondary axial skeleton, which we know as the vertebral column.
This is anunsegmented tube, which is widest behind.
The post-sacral part of the spinal column ossifies continuously, forming an unsegmented cylindrical rod, the urostyle.
These vertebrae are developed round an unsegmented rod, the =notochord=, which forms the axial support of the embryo.
The simplest and lowest types of both vertebrate and invertebrate animals have unsegmented skeletons; with the need for flexibility however segmentation arose both in the case of the invertebrate exoskeleton and the vertebrate endoskeleton.
A simple unsegmented notochord persists throughout life in the Cephalochordata, Cyclostomata, and some Pisces, such as Sturgeons and Chimaeroids.
The cranium may be compared to an unsegmented continuation of the vertebral column; (2) a number of ventral structures, disconnected or only loosely connected with the cranium.
It is probably equivalent to three vertebrae, the tenth, eleventh, and twelfth fused together, and to an unsegmented rod of cartilage which lies ventral to the notochord.
The =urostyle= is a long rod-like bone forming the posteriorunsegmented continuation of the vertebral column.
Each exopodite had a long, slender, unsegmented shaft, to which were attached numerous long, overlapping, flattened setae.
The spiders have the head and thorax fused, the abdomen unsegmented except in the most primitive suborder, and so appear even less trilobite-like than the insects.
The striking features of the appendages are the broad unsegmented exopodites which point forward all along the body, and the strong endopodites, which show practically no regional modification.
The typical nauplius has an oval unsegmented body and three pairs of limbs, corresponding to the antennules, antennas, and mandibles of the adult.
The anal segment is directly comparable to the pygidium of a Ceraurus, the stiff unsegmented uropods being like the great lateral spines of that genus.
Least satisfactory of all are traces of what are interpreted by the describer as a pair of long stiff unsegmented cerci or stylets on the last segment.
The specimen is quite imperfectly preserved, but seems to indicate that the exopodite of Ptychoparia had a long, rather narrow unsegmented shaft.
The very smallest specimens of Sao show a simple, unsegmented axial lobe, and the same simplicity has been noted in the young of other genera.
This difference does not, however, exist in the early larva, since in the larval Lepidosteus the haemal arches of the tail are unsegmented cartilaginous arches, as they permanently are in Elasmobranchii.
According to this view the head-kidney and its duct are to be looked on as the primitive and unsegmented part of the excretory system, more or less similar to the excretory system of many Trematodes and unsegmented Vermes.
The segments continue to increase regularly, each fresh segment being added in the usual way between the last formed segment and the unsegmented caudal lobe.
The crayfish's body is composed of a series of body-rings or segments; the toad's body is a compact apparently unsegmented mass.
It is composed of a series of chambers or segmental parts, which by a rhythmic contraction and expansion propel the blood anteriorly and into a short, narrow, unsegmented anterior portion of the vessel which may be called the aorta.
He found a strong positive argument for his theory that Vertebrates are descended from unsegmentedforms in the fact that the notochord arises as an unsegmented structure.
The vertebral column develops as a segmented structure round the notochord; the skull develops first as an unsegmented plate extending far beyond the notochord.
The common ancestor alike of unsegmentedworms and of all segmented types is probably the trochosphere larva, which in the Vertebrates is represented by the simple Keimblase or blastula.
He further showed that in the unsegmented but mature egg prelocalised cytoplasmic regions can be distinguished, which later become separated from one another through the segmentation of the egg.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "unsegmented" in a variety of sentences. We hope that you will now be able to make sentences using this word.
