Subclass Digenea
*General Characteristics
-they have at least two different forms: an adult stage and at least one larval stage.
-they have at least two different hosts in which the adults reside in specific organs, glands, or ducts.
-they are syncytial animals.
-they also have a tegument to aid in the transport of nutrition and is connected by cytoplasmic bridges.
-they have at least two different hosts in which the adults reside in specific organs, glands, or ducts.
-they are syncytial animals.
-they also have a tegument to aid in the transport of nutrition and is connected by cytoplasmic bridges.
Life Cycle |
-when an egg reaches fresh water, the operculum (lid-like hatch) opens up and a ciliated larva (miracidium) swims out.
-the miracidium swims until it finds an intermediate host in which it is attracted to. -it penetrates the host, losses its cilia, and develops into a sporocyst. -the sporocyst contain embryonic cells that develops into either daughter sporocysts or rediae (asexual reproduction). -this produces hundreds of the next larval stage, cercariae. The process of producing many cercariae is called polyembryony. -when the cercariae leave the host, it swims freely to a second hose, penetrates the host, and encysts as a metacercia. -when the final host eats the intermediate host, the metaceceria excysts and develops into an adult. |