Adenophorea or Aphasmidia was a class of nematode

Nematode

The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...

s (roundworms). It has been by and large abandoned by modern taxonomy

Taxonomy

Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

, because there is strong evidence for it being a motley paraphyletic group of unrelated lineages of roundworms.

Characteristics supposed to distinguish Adenophorea are:

• amphids always post-labial, variable shape, pore-like to elaborate
• deirids are not seen
• phasmids are generally absent
• hypodermal glands resent (excretory?) uninucleate
• simple non-tubular excretory system when present
• three caudal glands commonly opening through a spinneret at the tail tip
• male generally has two testes
• caudal alae are rare
• male with supplement glands in a single ventro-median row
• sensory papillae in cephalic region and along the body
• generally there are five esophageal glands
• marine, freshwater, terrestrial

As it seems, a number of these traits are plesiomorphic, and thus unsuitable to discern relationships.