This Hemigrapsus nudus has a large, ovigerous female parasite Portunion conformis (Isopoda) in its body cavity. The pink sac is a brood pouch, full of parasite eggs and larvae. Collected from Bamfield, BC.
This is "Rollie" my daughter's first pet... er I guess.Strobist: SB-800 with a diffuser on camera putting out a whole f/22 at point-blank range. Poor little Rollie has gotta be blind now.
Report on the zoological collections made in the Indo-Pacific Ocean during the voyage of H.M.S. 'Alert' 1881-2.London :Printed by order of the Trustees,1884. biodiversitylibrary.org/page/12067748