Euspongia, Hirudinaria, Meandrina, Chaetopleura, Carcharadon, Ctenplona, Fasciola, Bombyx, Ancylostoma |
1. | Gill slits are ventrally placed |
2. | Head and trunk are widened considerably |
3. | Distinct demarcation between body and tail |
4. | Their pectorals fins are distinctly marked off from cylindrical bodies |
1. | Squid, Devil fish, Flying fish, Dogfish |
2. | Apple snail, Pearl oyster, Brittle star, Brain coral |
3. | Sea urchin, Sea lily, Sea cucumber, Sea horse |
4. | Cuttlefish, Sea-hare, Tusk shell, Chiton |
1. | Presence of a swim bladder |
2. | Ventrally located mouth |
3. | Lack of operculum |
4. | Placoid scales |