Leeches
Leeches like Earthworms and Polychaeta worms are segmented worms usually under 3 inches long. A higher classification of the leech is clitellata include Similar to Earthworms Leeches are hermaphrodites (male and female sex organs) allowing them to reproduce with anyone in their species. When feeding leeches suck the blood of small invertebrates and then the blood moves from the jaws to its digestive track. In regards to the nervous system leeches have 2 cerebroid ganglions joined by a peri-oesophageal collar to a sub-oesophageal nerve mass.