"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift
January 25, 2010
January 25 - Branchellion torpedinis
Leeches are a class of annelids that has many members that feed exclusively on blood and are often found ectoparasitic on their hosts. Branchellion torpedinis is a piscicolid leech that infects a wide range of elasmobranchs (sharks, rays and skates). The individual shown here came from The Georgia Aquarium collection, but they can be found on cownose rays and sawfish along the Atlantic coast. The frilly gills on the side help with respiration. Unlike many leeches, which glue a handful of cocoons containing eggs to the substrate, this species is a supreme egg layer and instead casts large quantities of eggs into the water, more like a monogenean parasite.
Contributed by Alistair Dove.