Based on the anatomy and histology of the vas deferens of the brachyuran crab Scylla serrata, the vas deferens is classified into the proximal vas deferens (PVD), middle vas deferens (MVD), distal vas deferens (DVD) and the ejaculatory duct (ED), the latter opening into the intromittant organ. Proximal portion of PVD has cuboidal epithelial cells, secreting the substance A that encapsulises the sperm mass into spermatophores. The epithelial cells in the distal PVD region become columnar and secrete a granular material substance B to act as the medium for spermatophore transfer. Swollen MVD processes thin epithelial cells and stores the genital products pending ejaculation. Highly coiled DVD secretes a viscid, agranular substance C differing very much from substance secreted in the other regions. ED does not show any secretory activity, but appears to be filled with a substance D similar to that found in DVD. ED possesses a thick mesial muscular layer.

In the anomuran crab Clibanarius longitarsus, the proximal part of PVD possesses highly secretory cuboidal cells constituting the inner epithelial layer, the configuration of which significantly changes towards the distal part of PVD to give rise to a large typhlosole, the secretions which concentrate the loose spermatozoa into the sperm mass. In MVD, the epithelial cells are columnar in the lateral side of the lumen which is now elliptical. Here, the sperm mass is surrounded by a thick layer. The secretions accumulated in the ventral regions condense to form a cord which is attached to the pear-shaped ampule. In the DVD the lumen enlarges largely due to the thining of the lateral columnar epithelial cells. The spermatophore ampule is now kidney-shaped. The peduncle also get shortened and get connected to other spermatophores by a continuous gelatinous cord.