from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A larva of certain trematodes that is produced within the sporocyst and that can give rise to additional rediae or to cercariae.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the larva of some trematodes, some of which become cercariae
from the GNU version of the Collaborative International Dictionary of English
- n. A kind of larva, or nurse, which is prroduced within the sporocyst of certain trematodes by asexual generation. It in turn produces, in the same way, either another generation of rediæ, or else cercariæ within its own body. Called also proscolex, and nurse. See Illustration in Appendix.
from The Century Dictionary and Cyclopedia
- n. The second larval stage of some fluke-worms or Trematoda, as Distoma, intervening between the condition of the ciliated embryo and the more advanced form known as cercaria. A redia is a sporocyst, containing the germs of other rediæ, which eventually develop into cercariæ.
The period of development varies from ten to twenty weeks; each sporocyst may give rise to from five to eight _redia_ and each redia to from twelve to twenty _cercaria_.
The _daughter redia_ or _cercaria_, as they are now termed, leave the body of the snail and finally become encysted on the stems of grass, cresses and weeds.