Male reproductive system in Neorossia caroli

The male reproductive system of the bobtail squid Neorossia caroli (Cephalopoda: Sepiolidae) is described in detail, based on observations of 90 mature males caught from 500 to 1600m depth in Sardinian waters (western Mediterranean Sea). Reproductive organs in mature specimens accounted for up to 6% of total body weight. Of this, 70% was represented by the spermatophoric complex. Up to 83 spermatophores were found inside the Needham’s sac. Mean spermatophore length was 16.7 mm. Sperm mass, cement body, and ejaculatory apparatus represented 63.2%, 13.1%, and 23.7% of the total spermatophore length, respectively. Inverted spermatophores, empty spermatophore sheaths, and spermatangia were also found in the sac, and their presence is discussed. Spermatangia implanted in several parts of the bodies of males (e.g., head, funnel, and eyes) were recorded and their occurrence is discussed. The spermatophoric reaction was induced in the laboratory by submerging spermatophores in seawater, and it is described briefl