Note 8 — Chapter XIII · The Wavy Path of the Ameba and the Spiral Paths of Ciliates and other Organisms

Since this was written I have been able to examine the movement of live sperm cells in a number of representative animals, including the jellyfish Aurelia; the molluscs Ostrea, Solemya, Pandora; the arthropods Limulus and Anisolabia, and the vertebrates frog, turtle, snake, cat, dog and man, with the result that all these spermatozoa revolve on their long axes and swim in spiral paths resembling those of flagellates. Owing to their minute size their movements are made out only with great difficulty, but so far as could be determined all the sperms of any one species turn on their axes in the same way, that is, either right-handed or left-handed. Recently there has also come to my notice the very informing paper of W. D. Hoyt, 1910, in the Botanical Gazette, in which it is stated that fern sperms of various species swim in spiral paths.