Reciprocal copulation of <i>Siphopteron quadrispinosum</i>. Rolanda Lange Tobias Gerlach Joscha Beninde Johanna Werminghausen Verena Reichel Nils Anthes 10.1371/journal.pone.0043234.g001 https://plos.figshare.com/articles/figure/_Reciprocal_copulation_of_Siphopteron_quadrispinosum_/258074 <p>The bipartite penises, which are everted as largely translucent structures at the right front of the head (<b>h</b>), are reciprocally inserted into the partner. While the actual penis (<b>p</b>) is inserted into the gonopore (located behind the right parapod), the penile stylets (<b>s</b>) are hypodermically inserted into the foot of the partner. Markings are only shown for the lower animal.</p> 2013-02-20 00:27:26 copulation