Secernentea was a

class Class, Classes, or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used d ...

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 This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assignment is based on small subunit ribosomal DNA (SSU rDNA).

Description

Amphid apertures of Secernenteas are pore or slit-like. Some Secernenteas have deirids which are located near nerve ring. Secernenteas have posterior phasmids. The

excretory system The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism, so as to help maintain internal chemical homeostasis and prevent damage to the body. The dual function of excret ...

of a Secernentea is tubular. Cuticles of Secernenteas are striated in two to four layers. Lateral field is present. Secernenteas have three esophageal glands. Their esophageal structure varies. Male Secernenteas generally have one

testis A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is Homology (biology), homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of Androgen, androgens, p ...

. Caudal alae are common in Secernenteas. Sensory papillae of Secernenteas are cephalic only. It might be caudal papillae in male Secernenteas. Secernenteas are mostly found in land but they are rarely found in marine water or freshwater.

Taxonomy

Subclasses and

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

s of Secernentea are:

Tree of Life Web Project The Tree of Life Web Project (ToL) is an Internet project providing information about the diversity and phylogeny of life on Earth. This collaborative peer reviewed project began in 1995, and is written by biologists from around the world. The s ...

(ToL) (2002)
Nematoda
. Version of January 1, 2002. Retrieved November 2, 2008. * Subclass Rhabditia (paraphyletic?) **

Rhabditida Rhabditida is an order of free-living, parasitic and microbivorous nematodes living in soil. The Cephalobidae, Panagrolaimidae, Steinernematidae, and Strongyloididae seem to be closer to the Tylenchia, regardless of whether these are merg ...

** Strongylida * Subclass

Spiruria Spirurina is a suborder of nematode worms in the order Rhabditida. Spirurina contains a diverse group of worms that inhabit soil, water, and other bodies of organism. Footnotes References Ecdysozoa classes Obsolete animal taxa {{Secernentea-stub