Fig. 1

Libinia spinosa, males. a General view of testicular lobes surrounded by a fibrosous capsule (fc) enclosing groups of spermatids (sp) and spermatogonia (sg). b Detailed structure of a testicular lobe showing the epithelium of flatten cells with elongated nuclei (ep), different stages of sperm maturity (sp), spermatogonia (sg) in mitosis (arrows), accessory cells (ac) and space due the formation of the collecting testicular ducts (ctd). c Detailed structure of the testicular colleting duct showing the cubical epithelium (ep), spermatids (sp) and formation of spermatophores (arrows). d Detailed structure of the anterior vas deferens showing the columnar epithelium (ep), spermatids (sp) and formation of spermatophores (arrows). e Detailed structure of the proximal median vas deferens showing the columnar epithelium (ep) enclosing well-developed spermatophores (spf). f Detailed structure of ultimate median vas deferens showing the columnar epithelium (ep) enclosing the spermatophores (spf) embedded in a homogeneous seminal fluid (arrows). g Detailed structure of the well-developed musculature of the median vas deferens’s last portion. Epithelium (ep), musculature (mu), spermatophores (spf). h Anterior part of the posterior vas deferens showing the secretory epithelium (ep) enclosing the granular seminal fluid forming droplets (sf). i Terminal part of the posterior vas deferens showing the secretory epithelium (ep) enclosing the granular seminal fluid distributed homogenously (sf)