The Reproductive System of Gastrotrichs. III. Genital organs of Thaumastodermatinae subfam. n. and Diplodasyinae subfam. n. with discussion of reproduction in Macrodasyida¹

A comparative structural and ultrastructural investigation is made of genital organs of selected, genera of Thaumastodermatidae and their constructions are defined. Two new subfamilies are designated within the family based on reproductive features and other characteristics. The occurrence of bounding epithelia about the gonads, ova and central body region is noted. Paramyosin type muscles are noted for Platydasys. General and specific features of spermatogenesis, oogenesis and fertilization are defined and discussed. The evolution of accessory reproductive organs in Macrodasyida is discussed.