In this article we will discuss about the structure of Hermit Crab (Eupagurus) with the help of a diagram.1. It is commonly known as “hermit crab” and is found living in snail’s shells along sea shores.
2. Body is elongated, asymmetrical and is comprised of cephalothorax and abdomen.
3. Cephalothorax is conical and is covered by a hard carapace.
4. Mouth parts and some of the thoracic appendages are degenerate.
5. The cephalothorax bears a pair of stalked compound eyes, a pair of biramous antennule and a pair of uniramous antennae.
6. The thoracic appendages are represented by five pairs of walking legs of which first three are well developed and chelate and last two are greatly reduced. The first pair of walking leg bears unequal chela, used for closing shell aperture.
7. The abdomen is smooth, sharply curved un-segmented and bears 3 greatly reduced pleopods, a stumpy telson and a pair of small uropod’s.
8. The abdominal appendages of right side are degenerate.
9. These animals, while still very young, enter the empty gastropod shells and make the shell their permanent abode. They come out of the shell only at the time of feeding. The abdomen and hind part of cephalothorax are accommodated in the large body chamber of the gastropod shell.
10. Sexes are separate and development indirect.