Example: The bell animalcule (Vorticella sp.) [Laboratory exercise], [75.]

Other Protozoa.

Form of body, [78.]—Marine Protozoa, [80.]

XVI.—BRANCH PORIFERA: THE SPONGES.

Example: The Fresh-water sponge (Spongilla sp.) [Laboratory exercise], [84.]

Example: A calcareous ocean-sponge (Grantia sp.) [Laboratory exercise], [85.]

Example: A commercial sponge [Laboratory exercise], [86.]

Other Sponges.

Form and size, [87.]—Skeleton, [88.]—Structure of body, [88.]—Feeding habits, [88.]—Development and life-history, [89.]—The sponges of commerce, [90.]—Classification, [91.]