Updated publication reference for PubMed record(s): 25871631. Upon completion of spermatogenesis in crayfish testis, spermatozoa enter the vasa deferentia and are packaged into spermatophores that apparently function in the transfer of spermatozoa from male to the female during mating. In Astacidae and Parastacidae, spermatophores are deposited on the ventral surface of the female, where they remain for several days before initiation of ovulation and subsequent fertilization. This is accompanied by spermatophore morphological changes, suggesting that final maturation of decapod spermatozoa takes place in the seminal receptacle of the female