Annelid Worms: (concluded).

  Hirudinae (Leeches).

1. Annelids: Oligochaetes.

2. Leeches.

Leeches are macroscopic mostly free-living segmented worms with highly contractile, somewhat flattened muscular bodies bearing a sucker at each extremity. The head is at the narrower end, and has anywhere between two and ten small dark eyespots. The true segmentation is often obscured by much finer secondary rings called annuli.

More notes on leeches will be added when pictures more interesting than this one become available.
In the meantime, here is a diagram of a leech.