Morphological aspects of cytoplasmic droplets of some plethodontid salamander spermatozoa

Ultrastructural studies of cytoplasmic droplets of the spermatozoa of bulls, rams, rabbits, rats (Bloom & Nicander, 1961) and bats (Fawcett & Ito, 1965) revealed only numerous membranous vesicles and tubules in the matrix of the droplets. These authors agreed that the membranous elements were probably of endoplasmic reticulum and/or Golgi complex origin. The simplicity of the ultrastructure and lack of other organelles and inclusions in the droplet matrix led Fawcett & Ito (1965) to doubt suggestions that cytoplasmic droplets con-tain endogenous substrates for epididymal sperm survival. Recent biochemical and cytochemical analyses of cytoplasmic droplets in spermatozoa of different domestic animals (Dott & Dingle, 1968; Harrison & White, 1972; Moniem & Glover, 1972) showed a rather high activity of hydrolytic and glycolytic enzymes. Harrison & White (1972) suggested that at least some of the enzymes found in the seminal plasma may have their origin in disrupted cytoplasmic droplets. In our study (Martan, Brandon & Wortham, 1973) of interspecific variatio