ULTRASTRUCTURAL OBSERVATIONS OF THE MALE REPRODUCTIVE-SYSTEM AND SPERMATOZOA OF GORDIUS-AQUATICUS L, 1758

The male reproductive system of Gordius aquaticus L., 1758 is made up of two dorsolateral testis tubes that fuse at their posterior end by a vertical duct and lead via a single duct into the intestine. The test es have an epithelium that becomes disintegrated and is finally comple tely absent. After copulation, the mature spermatozoa modify their mor phology. Three different stages of spermatogenesis can be found in the male reproductive system, on the outside of the posterior end of the female and in the female seminal receptacle, respectively. The number of compartments in the spermatozoa diminishes. The shape of the cells varies from rod-shaped to filiform, but the length does not vary signi ficantly.