Vol. XXXII. January, 1917. No. i. BIOLOGICAL BULLETIN CYTOPLASMIC STRUCTURES IN THE MALE GERM CELLS OF RHOMALEUM MICROPTERUM BEAUV. HAROLD H. PLOUGH, ZOOLOGICAL LABORATORY, COLUMBIA UNIVERSITY. In a recent paper Lewis and Robertson gave an account of certain cytoplasmic structures in the male germ cells of Chor-thippus curtipennis Scud, as seen by the tissue culture method. It is the purpose of this paper to give somewhat similar data for the Florida lubber grasshopper, Rhomaleum micropterum Beauv., on the basis of both fixed and living material. My observations were made mainly in order to determine the origin and significance of the chromatoid body. They closely parallel those of the previous authors, and may perhaps clear up some doubtful points. While studying the maturation phenomena in Rhomaleum in 1914 it was found that a small round densely staining body was always present in the cytoplasm of the cells of the late growth period. Further study disclosed the fact that this body appeared in the very early growth period, enlarged up to the stage of dia-kinesis, and at both the first and second maturation divisions passed unchanged into one of the two daughter cells. During the metamorphosis of the spermatid this body passed gradually down into the tail region of the future spermatozoon, and was eventually cast off and degenerated in the lower end of the follicles. This history is exactly parallel to that of a similar but larger body described by Dr. E. B. Wilson ('13) in the spermatogenesis of the hemipter Pentatoma senilis, and called by him the "chroma-toid body." It is now known that a granule or granules of similar behavior are present in the developing male germ cells of the following forms: horse, pig, bull, rabbit, crayfish and
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