Class (Animalia): Secernentea

Secernentea was a class of nematodes in the Classical Phylogeny System (Chitwood, 1958) and is no longer in use. This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assignment is based on small subunit ribosomal DNA (SSU rDNA). 

Characteristics of Secernentea are:

• Amphid apertures are pore/slit-like
• Derids are present in some; located near nerve ring
• Phasmids are present; posterior
• Excretory system is tubular
• Cuticle is striated in two to four layers; lateral field is present
• Three esophageal glands; esophageal structure varies
• Males generally have one testis
• Caudal alae are common
• Sensory papillae are cephalic only; may be caudal papillae in males
• Mostly terrestrial
• Rarely found in fresh or marine water

Note: Technically this Animalia Class is no longer in use - once things get sorted out, it will be reclassified. But until then this is how it stands.
Reference: Wikipedia