Smaller crustaceans, produce eggs with hard resistant covering capable of surviving even a severe drought. These cysts are blown by wind and the species is dispersed. Freshwater crabs and prawns carry their eggs until they hatch out, while leeches carry the young in a pouch. Knowledge of Sri Lankan freshwater fauna has been considerably enhanced in the last twenty years or so in two ways. One is through the publication of monographs. The other way is through Swedish Expedition and Smithsonian Institution. Several animals groups were identified extensively from Sri Lanka, such as fish, amphibians, odonates and arthropods. Other freshwater fauna of Sri Lanka need more detailed work, which are currently based on the notes of way back in British period. According to the National Red Data List in 2012, many freshwater habitats are degraded at an alarming rate due to rapid human interference. Habitat destruction, fragmentation and loss of forest cover has increased in past decade rapidly. The result becomes severe, where many amphibians have been not recorded after their discovery, which led the scientists to categorize Sri Lanka as an biodiversity hotspot. Phylum: Amoebozoa Class: Tubulinea  Order: Tubulinida   Phylum: Ochrophyta Order: Actinochrysophyceae    Phylum: Amoebozoa Class: Tubulinea  Order: Arcellinida   Phylum: Amoebozoa Class: Tubulinea  Order: Arcellinida   Phylum: Dinoflagellata Class: Dinophyceae  Order: Gonyaulacales   Phylum: Cercozoa Class: Granofilosea  Order: Desmothoracida  Phylum: Ciliophora Class: Oligotrichea  Order: Choreotrichida   Phylum: Amoebozoa Class: Tubulinea  Order: Arcellinida   Phylum: Ciliophora Class: Ciliatea  Order: Sessilida   Phylum: Euglenozoa Class: Euglenoidea  Order: Euglenales   Phylum: Cercozoa Class: Imbricatea  Order: Euglyphida  Phylum: Ciliophora Class: Oligohymenophorea  Order: Tetrahymenida   Phylum: Amoebozoa Class: Tubulinea  Order: Arcellinida   Phylum: Ciliophora Class: Oligohymenophorea  Order: Hymenostomatida   Phylum: Ciliophora Class: Spirotrichea   Phylum: Ciliophora Class: Oligohymenophorea  Order: Peniculida   Phylum: Amoebozoa Class: Archamoebae  Order: Pelobiontida   Phylum: Myzozoa Class: Dinophyceae  Order: Peridiniales   Phylum: Ciliophora Class: Oligohymenophorea  Order: Peritrichida   Phylum: Chlorophyta Class: Chlorophyceae  Order: Chlamydomonadales   Phylum: Ciliophora Class: Oligohymenophorea  Order: Sessilida  Phylum: Bryozoa Class: Phylactolaemata  Order: Plumatellida    Phylum: Gastrotricha  Order: Chaetonotida   Phylum: Porifera Class: Demospongiae  Order: Spongillida   Phylum: Cnidaria Class: Hydrozoa  Order: Anthoathecata   Phylum: Rotifera   Sri Lankan freshwaters are home for 124 species of wheel animals.