2. Eupagurus (Hermit-crab) is a peculiar crustacean having extreme modifications in order to adjust in the coils of molluscan shells.
3.Body is reduced in varying degree and asymmetrical but shows usual divisions into head, thorax and abdomen.
4. Carapace is reduced and not fused at the sides with epistome. It covers the head. Rostrum absent.
5.Head contains antennules, antennae and stalked eyes. Thoracic appendages protrude through the opening of the shell. First thoracic leg is chelate and rest reduced. Right chelate leg is very large as compared to left and it acts as lid or operculum. Abdomen is asymmetrical, soft fleshy, elongated and twisted or bent under the thorax. Abdominal appendages of the right side absent while those of left side reduced. Sixth left abdominal appendages (uropod) adapted for holding the body in hollow objects.
8. Seventh and eighth thoracic appendages are reduced and remain inside the mollusc shell.
9.Uropods are hooked and notched in the shell.
10. Hermit-crab inside the gastropod shell and sea-anemone over the shell associate themselves to lead a commensal life. The hermit-crab by its appendages takes sea-anemone to varied places for food and in turn sea-anemone protects itself as well as the crab by its stinging cells. When the growth of the body demands, the Eupagurus selects a new large shell and deserts the old one. There is no metabolic dependency in above association.
Source:
1. Practical Zoology Invertebrates by S.S.Lal. 2. A Manual of Practical Zoology Chordates by Dr. P.S. Verma.
