"Male of Argonauta argo, with the hectocotylized arm still ontained in its enveloping cyst, four times enlarged." — Encyclopedia Britannica, 1893

Argonauta Argo

"Male of Argonauta argo, with the hectocotylized arm still ontained in its enveloping cyst, four times…

This illustration shows nerve cells from spinal ganglia.

Nerve Cells from Spinal Ganglia

This illustration shows nerve cells from spinal ganglia.

Nerve Ganglia, or Knots (sing. Ganglion; Knot) occur as collections of nerve cells on the course of a nerve, forming and obvious swelling. In surgery, it is the swelling caused by the collection of fluid in the fibrous sheath which surrounds a tendon. It arises from inflammation of the tendon-sheath, and occurs most often at the back of the wrist. Sometimes the cyst may be broken by firm pressure or by a smart blow, and the fluid be thus dispersed; or a puncture may be made, with proper antiseptic precautions, and the fluid be pressed out. Sometimes counter-irritation with iodine causes absorption. In any case, firm pressure with pad and bandage must be used afterwards, to prevent refilling until the cyst walls have united. This illustration shows a cross-section of a spinal cord and spinal nerve cells (g being ganglia).

Nerve Ganglia (Spinal)

Nerve Ganglia, or Knots (sing. Ganglion; Knot) occur as collections of nerve cells on the course of…

"Cyst containing spores, 5. cyst, 7. spores, 8. ducts"—Finley, 1917

Sporozoa containing spores

"Cyst containing spores, 5. cyst, 7. spores, 8. ducts"—Finley, 1917