CHAPTER 5 and 6

2. the down feathers.
7. embryos that draw nutrients from the yolk of the ovum.
9. has only single secretory cell.
14. produce milk.
17. the act of giving birth via viviparity.
18. process of forming an ectodermal tube,the neural tube.
22. with a fringe of projection along its posterior margin.
25. the time the embryo develops within the female.
31. produce an oily secretion,sebum.
32. a process wherein various protein products accumulate and collectively form keratin.
34. a cap of cells arched over a small blastocoel.
36. beneath the guard hairs and usually much finer and shorter.
37. type of feather lie close to the skin as thermal insulation.
39. it lacks on enamel,dentin and a vascular bone layer.

1. a diverse cell found in the skin of lampreys and other fishes.
3. meaning "organ" and "formation".
4. found in porcupines that are stiff,coarse hairs specialized for defense.
5. meaning "live" and "birth".
6. type of feather that constitute the major aerodynamic surfaces.
8. meaning "tissue formation".
10. meaning "egg" and "birth".
11. the cells resulting from these early cleavage divisions of the ovum.
12. union of two or more gametes.
13. meaning "gut" and "formation".
15. tissues that includes bones,cartilage,fibrous connective tissue,adipose tissue and the blood.
16. type of feather that aerodynamically shape the surface of the bird.
19. composed of many secretory cells.
20. usually found around the snouts of many mammals.
21. the act of laying eggs.
23. composed of concentric rings or circuli.
24. release of milk to a suckling.
26. characterized by the prevalance of thick surface coat enamel,without an underlying layer of dentin.
27. the contour feathers.
28. "bone formation".
29. are slender,keratinous filaments.
30. the base of a hair.
31. male gamete.
33. tissues are formed of closely adjoined cells with every little extracellular matrix between them.
35. female gamete.
38. type of feather that often specialized for display.