Reproduction

Female Reproduction

The female reproductive system of Somatogyrus depressus is very similar to that of Somatogyrus rheophilus. According to Thomson the ovary is confined to the upper whorl of the viscera and completely imbedded in the digestive gland. The primary oviduct passes along the ventral side of the digestive gland almost to the posterior wall of the mantle cavity. It then passes posteriorly to form an open loop alongside the albumen gland. Thomson goes on and says their egg capsule is dome-shaped and they usually lay their eggs on hard substrate.

Legend: ag=albumen gland; ast=anterior chamber of stomach; bu=bursa copulatrix; cg= capsule gland; di=digestive gland; emc=posterior wall of mantle cavity; gf=gill filaments; goo=ovary; got=testis; in=intestine; ki=kidney; op=operculum; ov=oviduct; pe=penis; pov=pallial oviduct; pr=prostate; sr=seminal receptacle; sv=seminal vesicle; vc=ventral channel; vd=proximal vas deferens; vd2=distal vas deferens.

Male Reproduction

The male reproductive system is very similar to Lepyrium except the penis lacks small dermal glands and is blade-like and slender (Thomson 1984). Somatogyrus depressus has relatively small testes. They take up no more than 67% of the length of the the visceral cord which lays behind the stomach (Hershler 1996). Thomson says the primary sperm duct lies along the mid-ventral side of the testes. The apical end is very slender but becomes greatly enlarged and convoluted in the second visceral whorl forming the seminal vesicle. After that it thins out forming the vas deferens which is above the prostate. The vas deferens courses through the left side of the penis and exits out the tip (Thomson 1984). He goes on to say the penis originates behind the right eye tentacle and when contracted curves into mantle in a counterclockwise fashion.

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Somatogyrus depressus (Tryon, 1863)

Reproduction