An Individual Barnacle, Semibalanus balanoides, with Two Penises
Journal of Crustacean Biology
Barnacle, Penis, Mating, Hemipenes, Semibalanus balanoides
During the late fall and early winter of 2007, we collected intertidal barnacles and observed reproductive activity. Among these, we found an otherwise normal barnacle that had two penises. At least one of these penises is inferred to have retained normal function and to have fertilized the egg brood of the barnacle's neighbor.
J. Matthew Hoch and Brian Yuen. 2009. An Individual Barnacle, Semibalanus balanoides, with Two Penises .Journal of Crustacean Biology , (1) : 135 -136. https://nsuworks.nova.edu/occ_facarticles/715.