It is not difficult in such compact species to distinguish between superficial cells, whose chief function is assimilation, subjacent cells charged with reserve material, and a core of tissue engaged in the convection of elaborated material from part to part.
Strata of volcanic rock subjacent to the city and its environs, and constructed originally for the interment of the Christian dead.
From the ventral surface of the collar nerve-tube numerous motor fibres may be seen passing to the subjacent musculature.
Thelyphonusassamensis d .Ventral surface of theanteriorregionof the opisthosoma, the first somite being pushed upwards and forwards so as to expose the subjacent structures.
The cells immediately subjacent to the superficial assimilating layer form a colorless, or nearly colorless, parenchymatous cortex, which acts as a food storage tissue (fig.
All living, and most extinct, Echinoderms show the following features, almost certainly due to an ancestral pelmatozoic stage: - An incomplete radial symmetry, of which five is usually the dominant number, is superimposed on the secondary bilateralism, owing to the outgrowth from the mouth region of one unpaired and two paired ciliated grooves; these have a floor of nervous epithelium, and are accompanied by subjacent radial canals from the water-ring, giving off lateral podia and thus forming ambulacra, and by a perihaemal system of canals apparently growing out from coelomic cavities.
Elkington showed that by cutting a deep drain through the clay, aided when necessary by wells or auger holes, the subjacent bed of sand or gravel in which a body of water is pent up by the clay, as in a vessel, might be tapped and the water conveyed harmlessly in the covered drain to the nearest ditch or stream.
The passage from this tegumentary layer to the subjacent longitudinal muscular one is gradual, no membrane separating them.
The body is covered externally by a chitinous cuticle which is a product of the subjacent epidermic layer in which no cell limits can be detected though nuclei are scattered through it.
In many Laminariaceae the thallus also grows regularly in thickness by division of its surface layer, adding to the subjacent permanent tissue and thus forming a secondary meristem.