The author used a bovine brain obtained from a slaughterhouse in one senior high school lesson. After giving a briefexplanation ofthe brain structure, the author letthe students first observe the apperance of the brain and then dissectit to observe the internal structure by themselves for one class period (50 min). From the students’ answers to the questionaire, this lesson seems to have been one ofthe mostimpressive lesson seems to have been one ofthe mostimpressive lessons given by the author in the 1987 school year. If it is available, the bovine brain seems to be good teaching material suitable for school lessons, because, 1) its dissection is very easy since it is big and tender, 2) it resembles the human brain in size and structure, and 3) it makes a strong impression on the students.

1. Morphological and distributional study of the stomata was made on various organs of Begonia semperflorens. The preparations were made by the method ofreplica using a colorless manicure solution.

・The stomata are found on such organs as the stems, stipules, petioles, laminae, bracts, sepals, petals and ovaries.

・The density ofstomata is highest on the under-epidermis ofthe laminae, and lowest on the epidermis of the stems.

・The density ofstomata is highest on the internodes epidermis in the middle part ofthe stems, compared with those in the other parts.

・Most ofthe stomata on the laminae, stems, ovaries, petioles, and stipules are in stomatal masses with 2 to 9 stomata, while the stomata on the bracts, sepals, and petals are in most cases isolated.

・The stomatal masses on the stems form a slender elliptical shape, and those on the laminae form a polygonal shape.

・Five stages ofthe differentiation of stomatal cells can be observed on the juvenile laminae.

2. Suggestions resulting from this investigation are follows :

・The stomata on the petals have a tendency to degenerate.

・The degree of density ofthe stomata on each ofthe organs is related to the number ofthe stomata that form the stomatal mass.

・A pair ofguard cells and three subsidiary cells resultfrom four cell divisions oftheinitial cell ofthe stoma.

3. The authors suggest that B. semperflorens provides the following effective teaching materials for an inquiry method :

・Students are able to presume the differentiation and the degeneration of stomatal cells in the stem by comparing the density ofstomata on each ofthe internodes.

・Students are able to presume thatthe sepals, petals and ovaries are derived from the leaves by comparing ofthe shape and the distribution of stomata on each organ.

・Students are able to constructthe model ofthe differentiating process ofthe stoma by observing a stomatal mass on a juvenile laminae.

A simple culture method for observation ofanimal development with free-living nematodes as teaching

materials was devised. The procedures ofthe method are as follows.

1) Nematodes were separated from soil by the Baermann funnel.

2) The nematodes were isolated from other microfauna by culture on sterilized potato blocks.

3) The nematodes and bacteria propagated on the potato blocks were inoculated on corn meal agar plate. On such an agar plate, the developmentprocess ofnematodes can be easily observed atschools by means of microscope.