- epithelial system
lies within the body wall, in close relation to nervous system and excretory system.
- hook
A small lump on the gubernaculum of the male tail. This structure lies on the ventral surface just anterior and central to the base of the spicule openings and contains a sensory structure called the hook sensillum.
- anal depressor muscle
a single, H-shaped cell which lies just above the anus and connects the roof of the anal canal to the dorsal bodywall; its contractions act to increase the size of the anal opening by lifting the roof of the rectum and hence facilitate expulsion of intestinal contents.
- dorsal ganglion
ganglion that lies beside the nerve ring in the head. It contains neuron cell bodies that send their neuronal processes into the ring and longitudinal nerves, but form no local neuropil separate from the nerve ring. The dorsal ganglion is in close contact with the dorsal hypodermal cord.
- pharyngeal nerve
A set of three longitudinal nerves (I1L, NSML and M2L) running along the anterior/posterior axis within the pharynx, each lying within a narrow groove created between syncytial pairs of muscles. One nerve lies dorsally, in close apposition to the dorsal gland duct, while the other two nerves lie subventrally.
- dorso-rectal ganglion
the ganglion that lies above and behind the rectum in the tail, in close continuity with the anal hypodermal ridge. It contains 3 neuron cell bodies (DVA, DVB and DVC) that send their neuronal processes into the ventral nerve cord via dorso-rectal commissures that encircle the anus. The ganglion contains no local neuropil in the hermaphrodite. In the adult male tail, this ganglion gains additional neurons and some local neuropil.
- ventral ganglion
ganglion lies beside the nerve ring in the head, just anterior of the retrovesicular ganglion. It contains about 20 interneuron and motorneuron cell bodies that all send their neuronal processes into the ring. The cell bodies are divided into two groups by the intrusion of the excretory duct and canal. The cells are bounded by a basal lamina which physically separates them from the lateral ganglion even though they are adjacent to one another.
- retrovesicular ganglion
Ganglion that lies at the anterior limit of the ventral nerve cord, near the ventral ganglion and nerve ring in the head posterior to the excretory pore. It is open and continuous with the region containing the motoneurons of the ventral cord. In the early L1 this ganglion holds 12 neuron cell bodies plus one neuroblast (Sulston and Horvitz, 1977; White et al., 1986). In the adult animal, the ganglion holds 20 neuron cell bodies.
- cuticular ala
Small linear ridges running along the lateral lines of the cuticle, lengthwise along the body; these thickenings lie in register with the seam cells which likely produce them and are present in the cuticle of the L1, dauer and adult stages, but not in other larval stages. The alae are suspected to provide better traction when the animal generates a bodywave. Since the animal usually lies on its side, the alae are in perfect position to catch against the substrate.