Exercise 5

1. A rear orifice, in some vertebrates, that serves as the only opening for the digestive, reproductive and urinary tracts.
7. The scientific name of a phylum of aquatic animals with pentaradial symmetry.
8. Hard diamond shaped scales.
9. The genus of the honey bee.
11. Worm blooded vertebrates characterized by the possession of feathers.

1. The scientific name of jawed fishes that possess a skeleton made entirely of cartilage.
2. The scientific name of exclusively marine molluscs characterized by a bilateral symmetry, a prominent head and a set tentacles or arms.
3. The scientific name of the infra-phylum of cylindrical jawless fishes.
4. Vertebrates characterized by a unique shell.
5. The scientific name of a super-class which includs all limbed vertebrates.
6. The dorsal body wall of a mollusc that hides the visceral body part.
10. They are distinguished by their limbless and greatly elongated body. The left lung is small or absent at all.