Comparative Anatomy (Chapter 7&8)

Across

1. Paired ventrolateral processes, remnants of the hemal arch bases that may receive the articulation with ventral ribs.
3. Often encroach upon the posterior margin of the skull roof.
6. In most mammals, the sternum consists of a chain of ossified elements in series, the _____.
8. Meckel’s cartilage, encased in dermal bone, usually remains unossified, except in some tetrapods where its anterior end ossifies as the _____ bone.
9. Centra with flat ends are _____ (amphiplatyan) and seem especially suited to receive and distribute compressive forces within the vertebral column.
11. Struts that sometimes fuse with vertebrae or articulate with them.
12. Ventral rib head.
15. Within cervical and lumbar regions, ribs exist only as remnants fused with transverse processes, forming what should properly be termed _____.
17. Served to anchor and support these arches.
18. A bony flap that covered the exit gill slits.
20. A collective term that refers to the fused cranial components immediately surrounding and encasing the brain.
21. Centra that are _____ bear saddle-shaped articular surfaces at both ends.
23. Formed from or within the integument, the dermis giving rise to bone and the epidermis to keratin.
24. Exhibits two centra per segment.
27. Mammals typically chew their food before swallowing it, a process termed _____.
29. An ancient chordate structure.
31. In nautical terminology applied to submarines, adjustment for vertical tilt is called “_____”.
35. A composite bony plate forming the floor of the shell.
40. _____ processes, projections that extend posteriorly from proximal rib segments.
42. Gives the vertebrate body shape, supports its weight, offers a system of levers that together with muscles produces movement, and protects soft parts such as nerves, blood vessels, and other viscera.
44. The first cervical vertebra.
45. A midventral skeletal structure that is endochondral in embryonic origin and arises within the ventral connective tissue septum and adjacent myosepta.
47. Forms deep within the body from mesoderm and other sources, not directly from the integument.
48. Takes its name from the nasolacrimal (tear) duct of tetrapods that passes through or near this bone.
50. Also form anti-twist, interlocking processes, or zygapophyses, between successive vertebrae.
51. Reinforced the ventral edge of the lower jaw.
53. Jaw-closing muscles are inserted on the _____ process, an upward extension of the dentary.
55. Abdominal ribs.
58. The hemal arches below expand into supportive struts, known as _____, to which the rest of the fin attaches.
59. _____ Process generally applies to any process extending from the centrum or the neural arch, but historically it has been used so loosely that it retains no exact morphological meaning
61. The reverse shape, concave posteriorly and convex anteriorly, characterizes centra that are _____.
62. Used as an equivalent term for the chondrocranium by some morphologists.
63. In many mammals, including humans, the distal end of the hyoid horn fuses with the otic region of the braincase to form the _____ process.

Down

2. Second hyomandibuladerived bone.
4. Where a hinge passes across the back of the skull, permitting rotation between the neurocranium and outer dermatocranium, the skull is said to exhibit _____.
5. Centra that are concave anteriorly and convex posteriorly are _____.
7. A long, continuous rod of fibrous connective tissue wrapping a core of fluid or fluid-filled cells.
10. In metamorphosed salamanders and in adult frogs, gill slits are absent, so excess water entering the mouth during feeding must reverse its flow to exit via the mouth. Such flow is said to be _____.
12. Underlies and supports the brain and is formed of endochondral bone or of cartilage, or both.
13. Ribs that meet ventrally with the sternum are _____ ribs.
14. In most _____ fishes, the axial column consisted of a prominent notochord.
16. If a joint passes through the dermatocranium behind the eye, the skull exhibits_____.
19. Consists only of Meckel’s cartilage in chondrichthyans.
22. Those false ribs articulating with nothing ventrally are _____ ribs.
25. In fishes and lower tetrapods, there also is an unpaired medial dermal bone.
26. As the ceratohyal, and to some extent the hyomandibula, have moved in to aid in supporting the jaws, the gill slit in front has become crowded, leaving only a small opening, the_____.
28. At the other end of the vertebral column, the posterior thoracic, lumbar, sacral, and, occasionally, caudal vertebrae fuse into a unit, the_____.
30. Processes that will be described more fully as we meet them during the survey of the axial column later in the chapter, project from centra and from their arches.
32. Amethod by which the animal rapidly grasps the prey with its jaws.
33. Openings in the outer dermatocranium.
34. Branchial arches that support the mouth.
36. Formed from the fusion of various bones in different species but usually includes the hyomandibula, various pterygoids, and quadrate.
37. A composite structure formed of three distinct parts.
38. If these vertebral processes fail to develop, the articular surface persists, forming a small concavity, the_____, to receive the rib.
39. In flying birds, the massive flight muscles arise from a large sternum that bears a prominent ventral keel, the _____.
41. Exhibits one centra.
43. Those that articulate with each other but not with the sternum are _____ ribs.
46. In most amphibians, reptiles, and birds, jaw suspension is _____.
49. These arriving streams of cells initially form enlarged clusters called _____ rings, arranged serially along the notochord.
52. Centra is absent.
54. If a joint in the dermatocranium passes in front of the orbits, the skull exhibits _____.
56. If each surface is concave, the centrum is _____, a design that seems to allow limited motion in most directions.
57. Means “horn”.
60. The anterior tooth-bearing part of the dentary.