title: Hatching in the monogenean parasite Dictyocotyle coeliaca from the body cavity of Raja naevus.
abstract: When eggs of the monogenean Dictyocotyle coeliaca, a parasite from the body cavity of Raja naevus, are incubated in alternating 12 h periods of light and darkness at 12 degrees C the marginal hooklets appear between 75 and 90 days after collecting the eggs from the host's body cavity and hatching begins after about 102 (96-109) days. Hatching occurs continuously throughout the light and dark periods so that there is no daily hatching rhythm, and host skin mucus and fluid from the host's body cavity (previously deep frozen and thawed before use) are ineffective as hatching stimulants. The significance of these observations in relation to host behavior is discussed.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D005393:Fish Diseases / Q000469:parasitology*; D005399:Fishes; D007814:Larva / Q000254:growth & development; D012623:Seawater; D013696:Temperature; D013997:Time Factors; D014200:Trematoda / Q000254:growth & development*; D014201:Trematode Infections / Q000469:parasitology / Q000662:veterinary*