The worm inhabits the lung of the frog and toad, and is hermaphrodite (Schneider) or parthenogenetic (Leuckart); the embryos hatched from the eggs find their way through the lungs into the alimentary canal and thence to the exterior; in a few days they develop into a sexual larva, called a Rhabditiform larva, in which the sexes are distinct; the eggs remain within the uterus, and the young when hatched break through its walls and live free in the perivisceral cavity of the mother, devouring the organs of the body until only the outer cuticle is left; this eventually breaks and sets free the young, which are without teeth, and have therefore lost the typical Rhabditis form.
During this stage the cuticle draws away from the imaginal cuticle which is forming beneath, ultimately becoming separated as a thin transparent pellicle through which the form of the adult can be seen.
The cuticle of a mushroom readily peels away from the flesh beneath, as shown at F.
The cuticle is a dead substance, and is composed in large part of chitin.
Sclerophyllous leaves are ually characterized by entire or sub-entire margins, a thick cuticle, riall but rarely sunken stomata, a we1l-developed and close-set ilisade tissue and a feeble system of air-spaces.
12) with very hard cuticle and somewhat abbreviated elytra, with over 2000 species, most of which live on decaying matter, and FIG.
The cuticle is frequently prolonged into spines and papillae, which are especially developed at the anterior end of the body.
The larvae of this parasite develop in the Malpighian tubules of the insect; at a certain stage they cast their cuticle and make their way into the space - part of the haemocoel - found in the labium.
The response to the action of light in diatropic leaves is, according to Haberlandt, due to the presence of epidermal cells which are shaped like a lens, or with lens-shaped thickenings of the cuticle, through which convergence of the light rays takes place and causes a differential illumination of the lining layer of protoplasm on the basal walls of the epidermal cells, by which the stimulus resulting in the orientation of the leaf is brought about.
The larvae of Elateridae are elongate, worm-like grubs, with narrow bodies, very firm cuticle, short legs, and a distinct anal proleg.
24), insects with rather soft cuticle, the elytra (often abbreviated) not fitting closely to the sides of the abdomen, the head constricted behind the eyes to form FIG.
They secrete a cuticle which never approaches in thickness the often calcified cuticle of Arthropods.
The body wall consists of an epidermis which secretes a delicate cuticle and is only ciliated in Aeolosoma, and in that genus only on the under surface of the prostomium.
The fungus mycelium grows between the cuticle and the epidermis, the former being ultimately ruptured by numerous short branches bearing spores (conidia) by means of which the disease is spread.
Exoskeleton The outer cellular layer (ectoderm or " hypodermis ") of insects as of other Arthropods, secretes a chitinous cuticle which has to be periodically shed and renewed during the growth of the animal.
The regions of this cuticle have a markedly segmental arrangement, and the definite hardened pieces (sclerites) of the exoskeleton are in close contact with one another along linear sutures, or are united by regions of the cuticle which are less chitinous and more membranous, so as to permit freedom of movement.
In the abdominal exoskeleton the segmental structure is very clearly marked, a series of sclerites - dorsal terga and abdominal sterna - being connected by pale, feebly chitinized cuticle, so that considerable freedom of movement between the segments is possible.
These consist of fine rods suspended between two points of the cuticle, and connected with nerve-fibres; they are known as chordotonal organs.
They lead into chambers, formed by inpushing of the cuticle, whose delicate inner walls are in contact with air-tubes; on the outer surface of these latter are ridges, along which the special nerveendings are arranged.
An ear of another type is found in the swollen second segment of the feeler in many male gnats and midges, the cuticle between this segment and the third forming an annular drum which is connected with numerous nerveendings, while the fine bristles on the more distal segments vibrate in response to the note produced by the humming of the female.
- A striking feature in the food-canal of the Hexapoda, as in other Arthropods, is the great extent of the " foregut " and " hind-gut," lined with a chitinous cuticle, continuous with the exoskeleton.
21, d) is revealed, exhibiting the wings and other imaginal structures, which have been developed unseen beneath the cuticle of the larva.
Sharp (1898), the marked divergence among the Hexapoda, as regards life-history, is between insects whose wings develop outside the cuticle (Exopterygota) and those whose wings develop inside the cuticle (Endopterygota), becoming visible only when the casting of the last larval cuticle reveals the pupa.
This cellular layer is called the hypodermis; it is protected externally by a cuticle, a layer of matter it itself excretes, or in the excretion of which it plays, at any rate, an important part.
Before a moult actually occurs the cuticle becomes separated from its connexion with the underlying hypodermis.
Concomitant with this separation there is commencement of the formation of a new cuticle within the old one, so that when the latter is cast off the insect appears with a partly completed new cuticle.
Metamorphosis is, from this point of view, the sum of the changes that take place under the cuticle of an insect between the ecdyses, which changes only become externally displayed when the cuticle is cast off.
An adult Hexapod is provided with a firm, well-chitinized cuticle and six conspicuous jointed legs.
25) - a vermiform podeiform Larva of larva, with soft, white, feebly-chitinized a Ground-Beetle cuticle and without either head-capsule (A epus marinus).
After a prolonged aquatic larval and nymphal life-history, the winged insect appears as a sub-imago, whence, after the casting of a delicate cuticle, the true imago emerges.
It cannot but suggest itself that this transference was induced by some peculiarity as to formation of cuticle, causing the growth of the wings to be directed inwards instead of outwards.
But the pupa hangs from the surface by means of paired respiratory trumpets on the prothorax, the dorsal thoracic surface, where the cuticle splits to allow the emergence of the fly, being thus directed towards the upper air.
Young animals always unlike parents, the wing-rudiments developing beneath the larval cuticle and only appearing in a penultimate pupal instar, which takes no food and is usually passive.
Pupa incompletely obtect or free, and enclosed in the hardened cuticle of the last larval instar (puparium).
Cuticle of pupa or puparium splitting longitudinally down the back, to allow escape of imago.
We are therefore entitled to assume that the suppressed wings of Exopterygota tend to reappear; and, speaking of the past, we may say that if after a period of suppression the wings began to reappear as hypodermal buds while a more rigid pressure was exerted by the cuticle, the growth of the buds would necessarily be inwards, and we should have incipient endopterygotism.
Externally is a thin cuticle; this covers the epidermis, which consists of a syncytium with no cell limits.
The outer surfaces of the mantle secrete' the shell, which is of the nature of a cuticle impregnated by calcareous salts.
The maceration of the soft parts of a scorpion preserved in weak spirit and the cleaning of the chitinized in-grown 1nus cuticle give rise to the false appearance of a limb axis carrying the lamellae.
Sutures are stated to mark off some of these pieces, but in the proper sense of that term as applied to the skeletal structures of the Vertebrata, no sutures exist in the chitinous cuticle of Arthropods.
It must always be remembered that we are liable (especially in the case of fossilized integuments) to attach an unwarranted interpretation to the mere discontinuity or continuity of the thickened plates of chitinous cuticle on the back of an Arthropod.
The mycelium of Sphaceloma grows just beneath the cuticle of the vine, through which it soon bursts, giving rise to a number of minute hyphae, which bear conidia.
The horsetails are remarkable for the large quantity of silica they contain in the cuticle (hence their value in polishing), which often amounts to half the weight of the ash yielded by burning them; the roots contain a quantity of starch.
The male next casts his cuticle, and by means of his spine bores FIG.
The epithelial layer consists of (1) so-called " indifferent " cells secreting the perisarc or cuticle and modified to form glandular cells in places; for example, the adhesive cells in the foot.
In such leaves, there are a well-marked cuticle, a thick epidermis, a thick hypodermis at least on the upper side of the leaf, well-developed palisade tissue, and a poorly developed system of air-spaces.
Cuculus canorus and trogons, is often lined with the broken-off hairs of these caterpillars, which, penetrating the cuticle, assume a regular spiral arrangement, due to the rotatory motion of the muscles of the gizzard.
As regards growth after hatching, all beetles undergo a "complete" metamorphosis, the wing-rudiments developing beneath the cuticle throughout the larval stages, and a resting pupal stage intervening between the last larval instal1 and the imago.
Such larvae, and also many with soft cuticle and swollen abdomen - those of the notorious "Colorado beetle," for example - feed openly FIG.
The cuticle contrasts strongly in its nature with the hypodermis it protects.
The growth of an insect is usually rapid, and as the cuticle does not share therein, it is from time to time cast off by moulting or ecdysis.
Swammerdam, however, showed the presence under the larval cuticle of the pupal structures.
He dabbed a bloody cuticle as we discussed how to handle the call.