Themiste (Lagenopsis) lageniformis (Baird, 1868)  

Unique among the Sipuncula, this species is known to reproduce by parthenogenesis. The main external characteristics, which differentiate T. lageniformis from it congeners are the flask-shaped body, the purple introvert collar and the absence of introvert hooks. It is considered the second most widely distributed sipunculan species in the Indian River Lagoon where it is found associated with oyster beds, among the empty shells.