Externally, the nephridium opens by a straight part of the tube, which is often very wide, and here the intracellular lumen becomes intercellular.
The nephridia in this group are invariably coiled tubes with an intracellular lumen and nearly invariably open into the coelom by a funnel.
This they take up into their protoplasm, where it is rapidly digested by being acted on by some intracellular digestive ferment (fig.
Nephridia generally paired, often very numerous in each segment, in the form of long, much-coiled tubes with intracellular lumen.
Methods have been introduced for the purpose of breaking up the bodies of bacteria and setting free the intracellular toxins.
In the blood of the owl resting, intracellular phases of both parasites alternate with active trypaniform ones; and, when in the former condition, Schaudinn considers that the parasites are identical with what have been formerly regarded as distinct Haemosporidia, Halteridium and a Leucocytozoon respectively.
With regard to the nature of intracellular toxins, there is even greater difficulty in the investigation and still less is known.
The action of these intracellular toxins has in many instances nothing characteristic, but is merely in the direction of producing fever and interfering with the vital processes of the body generally, these disturbances often going on to a fatal result.
They consist of a pair of tubules with an intracellular lumen running up the sides of the body, at times merely sinuous, at others considerably convoluted.
No sharp lines can be drawn, however, since many mycelia are intercellular at first and subsequently become intracellular (Ustilagineae), and the various stages doubtless depend on the degrees of resistance which the host tissues are able to offer.