ambulacral plates); Ampullæ and Tube feet. Make a general sketch and label.

5. Transverse section of arms, showing arrangement of Ossicles, Branchia, and Tube feet, the position of the Digestive glands, Radial canal, Ampullæ, and Radial nerve.

6. Write a definition of the group and compare with Arthropods.

Sea Urchin (Extra Work)

1. Aboral and oral views of Echinus showing ambulacral plates, ambulacral pores, and interambulacral plates. Trace all the resemblances you can between the external structure and that of the star fish. How might one be derived from the other?

X. MOLLUSCA

Pond Snail

1. Side view of pond snail showing Shell, Foot, Mantle, Tentacles, and Eyes.

2. Compare right-handed, left-handed, and flattened types of shells, and draw. Note Apex, Whorls, Sutures, Columella, Lines of growth, and Aperture. How does the shell grow and what causes the differences between the three kinds of shells?

3. Observe and describe the animal's method of breathing, its feeding, the movements of the rasp, the use of the feelers, the manner in which the body is protruded from the shell and retracted.

Field Slug

1. Side view of the slug, showing Foot, Mantle, Respiratory pore, Dorsal Tentacles, Ventral Tentacles, Eyes, and position of mouth. Compare with pond snail.

2. Place a slug on a glass plate, and note what effect touching the dorsal tentacle has upon its behavior. Make a series of at least 12 trials, touching the right and left tentacles alternately, and tabulate your results.

3. Make a series of at least 12 tests on the light responses of the slug, using the same method as you did with the earthworm.

4. Write a definition of the group to which the snail and slug belong, and compare with the Arthropods and Echinoderms.

Mussel

1. External view of right valve of a fresh-water mussel's shell, showing Hinge, Umbo, Lines of growth, etc. Note differences between the two ends.

2. Internal view of shell. Note: Muscle Scars, and other markings. (How formed?) Mantle line. Observe the three layers of shell: Epidermal, Prismatic, and Nacreous layers.

3. Side view of animal with left valve and left mantle removed, showing Mouth, Labial Palps, Foot, Intestine, Liver, Pericardial Chamber, Heart, Kidney, Gills, Right Mantle, Incurrent and Excurrent Siphons, Anus, Adductor, Protractor and Retractor muscles, Visceral Ganglion and Nerves.

4. Examine a portion of the gill with the microscope and look for eggs and embryos. Draw.

5. Draw a transverse section through the middle of the animal's body, X 2, showing the relation of parts, and observe especially the Suprabranchial chambers above the gills and the relations of pericardial and mantle chambers.

XI. VERTEBRATES

Fish

1. Side view of fish enlarged showing Mouth, Cloaca, Operculum, Nostrils, Eye, Lateral line, Fins, and Scales. Is there an ear? Eyelids? Observe types of fins: Paired Pectoral and Pelvic; medium Dorsal, Caudal, and Anal. Which correspond to arms and legs? Why?

2. Side view of head region, one operculum removed, showing mouth, gill arches, rakers, rays, and gill clefts.

3. Dissect off a small piece of the skin, note the arrangement of the muscles, and draw.

4. Expose the internal organs by removing body wall on one side. Sketch, noting: Heart, composed of auricle and ventricle; Liver; Stomach; Intestine; Kidney, Genital glands and ducts; Swim bladder; Pericardial cavity; and Colom. Expose the brain and draw. Note the Cerebrum, Thalamus, Optic lobes, Cerebellum, Medulla, Spinal cord, and Nerves.

5. Transverse section of fish enlarged, showing Integument; Lateral body muscle or Myotomes; backbone containing Notochord and Spinal cord; Swim bladder; Dorsal Aorta; Body Cavity; Intestine; Genital Glands, and Kidneys.

6. Observe and describe how the fish uses the different fins in swimming, and its manner of breathing.

7. Write a definition of the group to which the fish belongs. Compare with mollusks and Arthropods. In what respect is it most highly organized?

Frog

1. Side view of frog. Compare with the fish.

2. Expose internal organs; draw and compare with fish. Find, also, Spleen, Pancreas (between stomach and intestine), Lungs, Fat body, Bladder.

3. Compare, also, the general characteristics of the fish, frog, lizard. bird, and mouse; note down resemblances and differences.

XII. SUMMARY

Write a concise comparison of all the forms studied, bringing out especially the increasing complexity of structures from the Ameba to the Vertebrates.

XIII. EMBRYOLOGY
Development of Invertebrates

1. Study the models showing the development of various invertebrates, making notes on the cleavage of the egg, formation of blastula, gastrula, mesoderm, and sketch one or more larval forms. Compare larva with adult.

Metamorphosis of Frog or Toad

2. Observe and sketch the following stages: (a) newly laid eggsnote the darker Animal Pole of the individual egg and its enlargement as development advances; (b) Cleavage; (c) young Larva before hatching; (d) young Larva, just hatched (tadpole)-observe external

Gills, number? character? Suckers-use? tail, fin, etc.; (e) Internal Gill Stage-observe the single gill opening (on which side does it occur?), what other structures have appeared? (f) Posterior limb stage; (g) Anterior limb stage; (h) Absorption of tail (what becomes of it?); (i) young Frog.

3. Compare invertebrate and vertebrate development.

XIV. THE TISSUES

1. Examine prepared slides, both with the low and the high power, and make sketches of the following: (a) Ciliated Epithelium from mussel gill or roof of frog's mouth; (b) section of frog's Skin-note Epithelial cells of epidermis, Pigment layer, Connective tissue of dermis, Mucous Glands; (c) Cartilage of Ox; (d) transverse and longitudinal sections of Human Bone-observe Haversian Canals, spider-shaped Lacuna, threadlike Canaliculi, bone plates or Lamella-what is the use of each of these structures? Reconstruct a block of bone; (e) Visceral Muscle tissue from frog's stomach; (f) Skeletal Muscle tissue of grasshopper; (g) Nerve cells and Fibers; (h) frog's Blood.

2. Give your definition of a cell, a tissue, and an organ.

3. Study Indirect (Mitotic) Cell Division with the high power as seen in preparations of the salamander's skin or a growing onion root, and sketch several stages in division, including the resting cell.