The studies, described in this report and those that are to follow, consist of the physiological experiments on the shell movents with the purpose of improving the method of "Chemical Shucking" devised by Y. Tomiyasu and the author, based on the idea that the adductor muscles might be detached very easily with chemicals, after the shell has been opened a little by a physiological treatment. The results mentioned in the present paper are as follows. 1. The shell movements of Paphia philippinarum and Mactra veneriformis at ordinary temperature were investigated. a. In Mactra, the shells were kept open continuously during 24 hours, while in Paphia, the shells were perfectly closed several times during 24 hours. b. There was no regularity in movements in either of them. c. The movements of Mactra became dull and inert as the temperature lowered, while those of Paphia became inert with the lengthening of the total period of the closure (Figs. 3 and 6 ). 2. The changes in the movements until death, and those out of water, were investigated, and the difference between the movements of Paphia and those of Mactra, as well as the charateristic movements of both shell-fishes, was recognized distinctly (Figs. 7 ?10). a. In Mactra the shells were still opened even in an unfavourable condition such as the exposure in the air, and the evaporation of moisture from the body was prevented by closing together the borders of the mantles, while in Paphia the shells were closed longer than in normal cases. b. Paphia was more active than Mactra, but as it grew weak, the respective function of the smooth and striated muscles became unstable and indistinct. 3. In the case of raising the temperature from the room temperature to 50℃ at a rate of 1℃ per 2 min., the shell-fishes lost sensibilities and fell into heat coma at a certain temperature respectively. The temperature at which the shell-fishes lost their irritability and fell in to heat coma, was about 37℃ in Mactra veneriformis and Anadara subcrenata, and about 42℃ in Paphia philippinarum and Meretrix meretrix (Fig. 11).
1. 未だ研究されていないアサリ, シオフキの常温に於ける開閉殼運動を調査した. i. アサリは24時間中に数回完全に閉殻するが, シオフキは1回も閉殻しない. ii. 両貝共運動に規則性は認められない. iii. 低温ではアサリの開閉殼運動は不活発となり閉殼の総期間が長くなる傾向が見られるが, シオフキでは非常に緩かな鈍角的な運動を呈する. 2. アサリ及びシオフキが死亡する迄の期間に於ける運動の変化及び空中に露出した場合の運動の変化に就て調査し, 両貝の運動に於ける相違点及び非正常の環境に於ける両貝の特異な運動状態を明らかにした. i. シオフキは空中に露出した場合の如く甚しく不利な環境に於てもなお閉殼しない. その代り外套膜縁を伸して体水分の蒸発を防いでいる. 一方アサリは出来るだけ閉殼に努めている. ii. アサリはシオフキよりも生活力が旺盛であるが, 衰弱して来ると平滑筋及び横絞筋の作用が明確を欠くようになり, 開閉殻運動は漸次不分明なものとなる. 3. 常温より50℃迄温度を緩かに上昇せしめた場合アサリ, シオフキ, ハマグリ, サルボウの開閉殻運動が如何に変化するかを調査した. なお感受性を失い熱昏睡に陥る温度は夫々に特有なものであることを認めた.
Mendeley出力
