BBC News Health - Human Gland evolved from Gills
   The human parathyroid gland, which regulates calcium levels, probably evolved from fish gills, say researchers.
   http://news.bbc.co.uk/2/hi/health/4067039.stm

Endocrine Surgeon: Parathyroid
   Includes a history, symptoms, diagnosis, and related topics done in a easy to read format.
   http://www.endocrinesurgeon.co.uk/parathyroids/parathyroid1.html

Parathyroid.com
   Discusses diseases, symptoms, tests, and treatments, including mini-surgery.
   http://www.parathyroid.com/