Notes on animal associations. 1. A porcellanid crab on the sea pen, Pteroeides esperi Herklots

Abstract

Recently while examining a living specimen of the sea pen, Pleroeides esperi Herklots, brought up in a shore seine at Vedalai near Mandapam on the Gulf of Mannar, a porcel Janid crab, the colour pattern of which resembled that of the host to a remarkable degree, was found sheltering between the pinnules (plate I, fig. I). The camoufiage was so perfect that it was difficult at a casual glance to spot the crab, the general colour of which was whitish as that of the sea pen . while the carapace and chelipids had dark more or less symmetrically arranged spots, simulating to some extent the dark spots on the distal part and margin of the pinnules.