The bipartite penises, which are everted as largely translucent structures at the
right front of the head (h), are reciprocally inserted into the partner. While the actual penis (p) is inserted into the gonopore (located behind the right
parapod), the penile stylets (s) are hypodermically inserted into the foot of the partner. Markings are only shown for the lower animal.
Citation: Lange R, Gerlach T, Beninde J, Werminghausen J, Reichel V, et al. (2012) Female Fitness Optimum at Intermediate Mating Rates under Traumatic
Mating. PLoS ONE 7(8): e43234. doi:10.1371/journal.pone.0043234