1.   The so-called excretory system is very primitive, consisting of a canal within each lateral cord joining at the excretory pore in the oesophageal region.

2.   Cervical papillae occur anteriorly in the oesophageal region, and caudal papillae posteriorly at the tail.

3.   Cephalic and cervical vesicles are inflations of the cuticle around the mouth opening and in the oesophageal region.

4.   A most useful generic character is the distinct excretory notch in the oesophageal region.