Hind-feet with a very short nailless first toe, the second, third and fourth toes partially united by integument, of nearly equal length, the fifth distinct and rather shorter; all four with long and curved nails.
In this it remains until the completion of the transformation into the sexually mature insect, which then emerges from the case, leaving the pupal integument behind.
The surface of the neck is covered by integument forming the floor of the branchial cavity.
Cephalic shield continuous with dorsal integument; no shell; ctenidium projecting from mantle cavity.
The ctenidium is atrophied, and the edge of the mantle-skirt is fused to the dorsal integument by concrescence, except at one point which forms the aperture of the mantle-chamber, thus converted into a nearly closed sac. Air is admitted to this sac for respiratory and hydrostatic purposes, and it thus becomes a lung.
A remarkable cord of cells having a position just below the integument occurs on each side of the head.
While furnishing - almost unconsciously, however - additional evidence for overthrowing that classification, there is, nevertheless, no attempt made to construct a better one; and the elaborate tables of dimensions, both absolute and proportional, suggestive as is the whole tendency of the author's observations, seem not to lead to any very practical result, though the systematist's need to look beneath the integument, even in parts that are so comparatively little hidden as birds' feet, is once more made beyond all question apparent.
The spider owes its name Argyroneta or the silver swimmer to its silvery appearance as it swims about under water enveloped in air, and its power to retain an envelope of air on its sternum and abdomen depends upon the circumstance that these areas are beset with hairs which prevent the water reaching the integument; but the air retained by these hairs can be released when the spider wishes to fill its subaqueous home with that element.
The nature of the integument and its hairy clothing in all spiders enables them to be plunged under water and withdrawn perfectly dry, and many species, even as large as the common English house-spider (Tegenaria), are so lightly built that they can run with speed over the surface of standing water, and this faculty has been perfected in genera like Pirata, Dolomedes and Triclaria, which are always found in the vicinity of lakes or on the edges of rivers and streams, readily taking to the water or running down the stems of water plants beneath its surface when pursued.
The connective tissue of the integument and basement membrane imperceptibly merges into that which surrounds the muscular bundles as they are united into denser and definite layers, and this is especially marked in those forms (Akrostomum) where the density of the muscular body-wall has considerably diminished, and the connective tissue has thus become much more prominent.
To it belong (a) superficial grooves or deeper slits situated on the integument near the tip of the head, (b) nerve lobes in immediate connexion with the nervous tissue of the brain, and (c) ciliated ducts penetrating into the latter and communicating with the former.
Its integument is marked by a large number of transverse grooves simulating the segmentation of Annelids, and near the anterior extremity close to the mouth are two pairs of recurved chitinous hooks.
The soft integument and limbs of the mesosoma have been removed as well as all the viscera and muscles, so that the inner surface of the terga of these somites with their entopophyses are seen.
The entosternite was probably in origin part of the fibrous connective tissue lying close to the integument of the sternal surface - giving attachment to muscles corresponding more or less to those at present attached to it.
This telson may enlarge, it may possibly even become internally and sternally developed as partially separate somites, and the tergum may remain without trace of somite formation, or, as appears to be the case in Limulus, the telson gives rise to a few well-marked somites (mesosoma and two others) and then enlarges without further trace of segmentation, whilst the chitinous integument which develops in increasing thickness on the terga as growth advances welds together the unsegmented telson and the somites in front of it, which were previ ously marked by separate tergal thickenings.
- Integument hard, strengthened by a continuously chitinized dorsal and ventral sclerite.
- Integument mostly like that of the Cryptostigmata.
- Integument soft, strengthened by special sclerites, those on the ventral surface of the prosoma apparently representing the basal segments of the legs embedded in the skin.
In the remainder the segmentation involves primarily the genitalia and includes the integument, muscles and part of the excretory system.
The excretory tubes, the nervous system, and the parenchyma and integument are continuous from one end of the worm to the other.
As growth proceeds the integument is periodically cast; and at the final moult the perfect winged insect appears.
Through this temporary protection the active pupa, which closely resembles the mature insect, subsequently bites a way by means of its strong mandibles, and rising to the surface of the water casts the pupal integument and becomes sexually adult.
The muscular tissue of the dorsal body-wall is much reduced and the integument here is thin and FIG.
Blumrich, "Das Integument der Chitonen," Zeitsch.
These are likely to have been produced by the ripe genital glands, which may have extruded their products directly through the membranous integument of the under side.
Our outside and often thin and fanciful clothes are our epidermis, or false skin, which partakes not of our life, and may be stripped off here and there without fatal injury; our thicker garments, constantly worn, are our cellular integument, or cortex; but our shirts are our liber, or true bark, which cannot be removed without girdling and so destroying the man.