11. Unlike many other gastropods, they are more or less bilaterally symmetrical in their external appearance. 12. Both bipinnaria and brachiolaria larvae are bilaterally symmetrical . 13. The cleavage of bryozoan eggs is biradial, in other words the early stages are bilaterally symmetrical . 14. The patterns are not perfectly bilaterally symmetrical and can vary between different individuals in the species. 15. The generalized mollusc is bilaterally symmetrical and has a single, " limpet-like " shell on top. 16. The approximately 400 species of flatfish also lack symmetry as adults, though the larvae are bilaterally symmetrical . 17. In bilaterally symmetrical organisms there is often a major mesentery separating the two halves of the coelom. 18. This shell spoon is not bilaterally symmetrical . 19. In bilaterally symmetrical animals, nervous tissues concentrate at the anterior region, forming structures responsible for information processing. 20. The gray leaves are covered with soft hairs, with bright red bilaterally symmetrical flowers growing in pairs.
