Gamasomorpha cf. vianai Birabén, 1954

SPERM TRANSFER FORM (fig. 9): Very large (.30 Mm), cone-shaped synspermia that presumably comprise four sperm, which are loosely arranged (fig. 9A, B). In the periphery of the sperm conjugate irregular tubelike membranes, originating from membrane invaginations, are visible (fig. 9C). The cytoplasm is heterogeneous, numerous electron-dense droplets and lamellae are visible (fig. 9B, C). The nuclei are elongated, cross sections reveal helical contortion, indicated by curls of the nuclei (fig. 9B). Numerous mitochondria are present. A thin, homogeneous secretion sheath (, 80 nm) surrounds the sperm conjugates (fig. 9A, C). The chromatin of mature spermatozoa is irregularly condensed (fig. 9D).

SPERMATOZOA (figs. 9): Acrosomal complex: AV cylindrical; narrow subacrosomal space, (fig. 9C). AF originates from the subacrosomal space, extends into NC. Nucleus: prcN elongated (fig. 9A, B), with conspicuous chromatin-condensation pattern (fig. 9A, D). Implantation fossa very small and contains only centrioles. peN not identifiable. NC located in the periphery, empty for the most part. Axoneme: short, indicated by only few cross sections that are visible in the sperm conjugate (fig. 9B); 9+3 axonemal pattern (fig. 9B).

NOTES ON SPERMIOGENESIS (fig. 10): The small developing acrosomal vacuole with a narrow subacrosomal space (fig. 10A inset) separated from the nucleus by a distinct electron-dense plate (fig. 10A). At the posterior pole of the nucleus both centrioles migrate toward the latter, initiating the formation of a small implantation fossa (fig. 10B). The nucleus elongates markedly while the chromatin condenses irregularly, resembling an electron-dense thread in midspermatids (fig. 10C). Mature spermatozoa remain the irregularly condensed chromatincondensation pattern (fig. 10D, E). At the end of spermiogenesis four spermatids fuse (fig. 10E) to form a very large sperm conjugate. The manchette of microtubules disintegrates during further sperm conjugate differentiation.