Figure 1
From: Thalassophryne nattereri fish venom: from the envenoming to the understanding of the immune system

The venom apparatus of Thalassophryne nattereri is composed of two dorsal and two lateral canaliculated spines covered by a membrane connected to the venom glands at the base of the fins. When the spine penetrates the victim, the integumentary sheath enclosing the gland press out the venom into the duct.