The seed itself is of a Cycadean type, and radially symmetrical.
We may, with Sedgwick, suppose the coelom to have originated by the enlargement and separation of pouches that pressed outwards from the archenteron into the thickened body-wall (such structures as the genital pouches of some Coelentera, not yet shut off from the rest of the cavity), and they would probably have been four in number and radially disposed about the central cavity.
A circlet of radially situate infrabasals (IBB) may also be present.
In some hydroids the founder-polyp, developed from a planula after fixation, throws out numerous outgrowths from the base to form the hydrorhiza; these outgrowths may be radially arranged so as to form by contact or coalescence a flat plate.
When the rod extends or contracts longitudinally it contracts or .(- -U P extends radially and in the ratio a, known as Poisson's ratio, which in metals is not far from 4.
The nervous system consists of a ring below the suckers and of a large number of radially arranged tracts running forwards and backwards.
The two are carried on a common frame, so arranged that a change in form of the spring causes a relative displacement of the disk and roller, the point of contact moving radially from or towards the centre of the disk.
There is only one right and one left lobe, each traversed through its whole length by a mesobronchium, whence arise about ten secondary bronchia; these send off radially arranged parabronchia, which end blindly near the surface.
Pectolite is a secondary mineral occurring as white masses with a radially fibrous structure in the veins and cavities of basic igneous rocks.
The current to be measured is passed through the coils of the electromagnet, then enters the mercury disk at the centre, flows through it radially in all directions, and emerges at the periphery.