根据课文的内容在每个空白处填入一个恰当的词。
In ten minutes I had seen all that could be seen in the fish, and started to look for the professor—who had, however, left. Half an hour ___61___—an hour—another hour; the fish began to look disgusting. I turned it ___62___ and around; looked it in the face—ghastly; from behind, beneath, above, sideways—just ___63___ ghastly. I ___64___ not use a magnifying glass, ___65___ instruments of any kind. Just my two hands, my two eyes, and the fish: it seemed a most limited ___66___ of study. With a feeling of desperation again I looked at that fish. I pushed my finger down its throat to feel how ___67___ the teeth were. I began to count the ___68___ in the different rows, until I was convinced that was nonsense. At last a happy thought struck me—I would ___69___ the fish; and now with surprise I began to ___70___ new features in the creature.