1. Fig. 23-1, p.360

2. Table 23-1, p.361

3. Fig. 23-2, p.361 ventral posterior dorsal anterior

4. Fig. 23-3, p.363

5. Fig. 23-6, p.364 choanoflagellates placozoansspongescnidariansflatwormsrotifersmollusksannelidsroundwormsarthropodsechinodermschordates multicelled body no true tissues true tissues radial ancestry, two germ layers protostomes, mouth forms first in embryos bilateral ancestry, three germ layers deuterostomes, anus forms first in embryos fungi

6. Fig. 23-7, p.365

7. Fig. 23-8, p.365 nucleus glassy structural elements ameboid cell pore semifluid matrix flattened surface cells collar cell central cavity water out water in water in flagellumcollar of microvilli

8. Fig. 23-9, p.366

9. Fig. 23-10, p.366 capsule's trigger (modified cilium) lid barbed thread in capsule nematocyst (capsule at free surface of epidermal cell) barbs on discharged thread exposed

10. Fig. 23-11, p.367

11. Fig. 23-12, p.367 male medusa ciliated bilateral larvagrowth of a polypone branch of a colony ovum sperm zygote feeding polyp reproductive polyp female medusa

12. Fig. 23-13, p.368 rudimentary brain (pair of large ganglia in head) branching gut pharynx; protrudes onto food, then retracts into the body between feedings ovary testis oviduct genital pore pair of nerve cords that have lateral branchings

13. Fig. 23-14, p.369

14. Fig. 23-15, p.369 proglottids Larvae, each with inverted scolex of future tapeworm, become encysted in intermediate host tissues (e.g., skeletal muscle). A human, the definitive host, eats infected, undercooked beef, which is mainly skeletal muscle. Each sexually mature proglottid has female and male organs. Ripe proglottids containing fertilized eggs leave the host in feces, which may contaminate water and vegetation. Inside each fertilized egg, an embryonic, larval form develops. Cattle may ingest embryonated eggs or ripe proglottids, and so become intermediate hosts. one proglottid scolex attached to wall of intestine scolex

15. Fig. 23-16, p.370

16. Fig. 23-17, p.370

17. Fig. 23-18, p.371

18. Fig. 23-20, p.372

19. Fig. 23-21, p.373

20. cuttlebone arm jaw tentacle radula siphon brain esophagus kidney stomach gill anusink sac heart accessory heart reproductive organ mantle

21. Fig. 23-22, p.374 false coelom (unlined body cavity) intestine eggs in uterusgonad muscular body wall pharynx anus

22. Fig. 23-23, p.374

23. Fig. 23-24, p.375

24. Fig. 23-25, p.376 chelicerae

25. Fig. 23-27, p.377

26. Fig. 23-32, p.379

27. Fig. 23-33, p.380

28. Fig. 23-34, p.381