The miracidium is the small free-swimming larva of some Trematoda including the Schistosoma. It normally hatches from eggs present in its host's faeces. When hatched in free-standing water the miracidium typically swims and finds a particular species of snail to continue its life cycle in. The Trematoda is a class within the phylum Platyhelminthes, which contains two groups of parasitic worms. ... A genus of trematodes, Schistosoma spp. ... Rabbit feces are usually 0. ... Giant African Snail (Achatina fulica) The name snail applies to most members of the molluscan class Gastropoda that have coiled shells. ...

In its snail host it becomes a sporocyst, which produces cerceriae, which emerge and search for a host according to species.

The cercaria is somewhat like a small adult, but has a large swimming tail somewhat like a tadpole's (but without a notochord or backbone, as it is not a chordate). Ten-day-old tadpoles Embryos (and one tadpole) of the wrinkled frog (Rana rugosa) A tadpole (also known as a pollywog) is a larval frog, toad, salamander, or newt. ... The notochord consists of a rod of cells situated on the ventral aspect of the neural tube; it constitutes the foundation of the axial skeleton, since around it the segments of the vertebral column are formed. ... In general usage, the backbone is a synonym for the spine of an animal. ... Typical Classes Subphylum Urochordata - Tunicates Ascideiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with...

With some species of Trematoda the cercaria develops into an adult in that host.

With other species of Trematoda (for example Ribeiroia) the cercaria encysts, and waits until the host is eaten by a third host, in whose gut it emerges and develops into an adult.

In its final host, it eventually lays eggs which are discharged in its host's faeces. From there the eggs hatch in the presence of free water and the miracidium stage of life is reached again.