A large number of corals, both aporose and perforate, are colonial.
The inner surface of their cup-shaped mouth is armed with pointed teeth, with which they perforate the integuments of the fish attacked, scraping off particles of the flesh and sucking the blood.
In order to measure the pH directly; the kit includes a plastic auger to perforate the ground.
The life-history of Schistostomum haematobium is still unknown, but the difficulty in obtaining developmental stages in any of the numerous intermediate hosts that have been tried suggests that the ciliated larvae may develop directly in man and either gain access to him by the use of impure water for drinking or may perforate his skin when bathing.
In favour of seeing in the lateral trunks and their branches a vascular system, is the contractility of the former, and the fact of the intrusion of the latter into the epidermis, matched among the Oligochaeta, where undoubted blood capillaries perforate the epidermis.