Body continued into one or two caudal appendages, which bear hollow papillae. The papillae are ventral to the anus. The introvert forms 1/4 to 1/3 of the total body length; it is covered with spines in conspicuous longitudinal rows. The rest of the body is ringed. The retractor muscles are numerous and are attached to the body-wall, some anteriorly and some posteriorly.
The following species of this genus occurs in the region:
Priapulus caudatus