The cilia exist at the anterior end, and extend down a lateral fissure as in Vorticella.
The lateral fissure of Sylvius is relatively wide and open, and this and other features suggest the brain of the anthropoid.
At other times, finding for itself some weak place in the cone, it may flow out by a lateral fissure, g.
Margins of the shell dentate along the lateral fissure, on each side of one valve thirteen or fourteen thin conical teeth.
The water may have been only diverted by the shock and might be found again at the lower level, or in some lateral fissure.