In this article we will discuss about the structure of Sea Mouse (Aphrodite) with the help of a diagram.
2. Body elliptical and bears a distinct head.
3. Triploblastic, bilaterally symmetrical, metamerically segmented and coelomate animals.
4. The head bears a pair of jointed palp and an unpaired tentacle.
5. Soft, hair like and elongated setae are present all over the back of animal and form a felt or blanket like covering over the body.
6. On sides the setae are long and in bundles and have a peculiar characteristic that they shine when light falls on them and thus are called iridescent bristles.
7. Along the back are also present brown and small stiff chaetae (setae) which act as organs of offence and defense.
8. Parapodia are differentiated into a dorsal notopodium and a ventral neuropodium. The Notopodium is comprised of the aforesaid iridescent stiff and soft normal setae. The neuropodium is comprised of only soft and hair-like setae.
9. The dorsal cirri of notopodium is modified into a fan-like elytra, which is accommodated in the space between notopodium and body wall and acts as respiratory organ.
10. During locomotion the iridescent bristles give an impression of change of colour from brown to golden (Iridescence).
11. When frightened, the animal rolls into a small ball with the erection of stiff chaetae, which act like spines of porcupine.