An important fact to note is that the blastopore is included in this overgrowth of epiblast, so that the neural tube remains for some time in open communication with the archenteron by means of a posterior neurenteric canal.
There is, strictly speaking, no invagination (emboly), but an overgrowth (epiboly) of the smaller cells to enclose the larger.
These are probably important in checking overgrowth by encrusting organisms, and in particular by preventing larvae from fixing on the zoarium.
Into the legendary overgrowth of the First Crusade we cannot here enter any further 2; but it is perhaps worth while to mention that the French legend of the Third Crusade equally perverted the truth, making Richard I.
In spite of the frequent overgrowth of a luxuriant imagination, the leading ideas of really primitive cosmogonies are extremely simple.
The continued use of large doses of alcohol produces chronic gastritis, in which the continued irritation has led to overgrowth of connective tissue, atrophy of the gastric glands and permanent cessation of the gastric functions.
And even when recognised at last, their immense magnitude renders it very hard really to believe that such bulky masses of overgrowth can possibly be instinct, in all parts, with the same sort of life that lives in a dog or a horse.
The primordium of the neurochord (neural or medullary plate) referred to above becomes closed in from the surface by the overgrowth of surrounding epiblast, and its edges also bend up, meet, and finally fuse to form a tube, the medullary or neural tube.
Apart, however, from self-defence, the main causes of war are four: (I) The desire for territorial expansion, due to the overgrowth of population, and insufficiency of the available food-supply; if the necessary territory cannot be obtained by negotiation, conquest becomes the only alternative to emigration to foreign lands.
Solenia, Cyphella - and even simpler cases are met with in Mortierella, where the zygospore is invested by the overgrowth of a dense mat of closely branching hyphae, and in Gymnoascus, where a loose mat of similarly barren hyphae covers in the tufts of asci as they develop.