Description (from Thorne, 1939)
Body assuming the form of an open letter C, especially when killed by gradual heat. Transverse striae indistinct. Cuticle with a distinct outer layer which is especially conspicuous on the tail. Amphid apertures half as wide as head. Lateral cords one-seventh as wide as body. Tooth very slender, three-fourths as long as the head width and hollow only one-third its length. Second and third sections of pharynx obscure. Esophagus enlarged by gradual expansion slightly anterior to middle, the enlarged portion frequently exhibiting a hyaline, columnar structure, especially in the posterior section. Ovaries reflexed four-fifths the distance back to the vulva. Males unknown from among several thousand specimens observed at all times of the year.
Habitat: The most prevalent nygolaim of the Western United States. Collected from cultivated valley soils of Utah, Idaho, California, Colorado, and Oregon.