The pattern of chromatin condensation in the developing sperm nucleus of the scorpion,Centruroides vittatus, is described. The chromatin fibrils become especially distinct and remain well defined until quite late in spermiogenesis. The fibrils that compose the chromosomes are arranged in groups. The chromosomes in this species have diffuse kinetochores. The sperm head is helical in the swimming sperm and acquires this shape without the influence of microtubules, which are not present. Also absent is the centriole adjunct, though this organelle is found in other scorpions.