Ultrastructure of the Phasmids of Scutellonema brachyurum.

Electron microscopical studies reveal that the phasmids of Scutellonema brachyurum include socket and sheath cells which appear to be secretory. The phasmid includes an external cup-shaped ampulla filled with electron-dense material which may be lipopolysaccharide. The ampulla is continuous, with a receptor cavity surrounded by the socket and sheath cells. The dendrite receptor originates from a neuron and directs posteriorly through a receptor socket into the receptor cavity ending near the electron-dense plug. Serial sections through the dendrite receptor indicate that it does not conform to the typical 9+2 arrangement of microtubules characteristic of cilia in higher animals.