Sporosac springing from m, a modified hydriform person (blastostyle): the genitalia are seen surrounding the spadix or manubrium.
The intervening segments contain the genitalia, which are on the Oligochaeta plan in that the gonads are independent of their ducts and that there are special spermathecae, one pair.
In the remainder the segmentation involves primarily the genitalia and includes the integument, muscles and part of the excretory system.
The compound organism now develops two sets of inter-connected genitalia and becomes a Diplozoon.
The Nematomorpha form an isolated group; at first sight they seem to be connected with the Nematoda, but in reality their only common feature is the tubular genitalia opening into a cloaca, and it seems at present impossible to connect them with the Annelida.
The young leave the cocoon as fully formed earthworms in which, however, the genitalia are not fully developed.