A new hemogregarine from marine fishes.

Haemogregarina uncinata sp. n. is described from the blood of 2 marine eelpouts, Lycodes lavalaei and Lycodes vahlii (Perciformes: Zoarcidae). Erythrocytic schizogony occurred in peripheral and cardiac blood, but mature schizonts were restricted to the latter site. Mature and rupturing schizonts contained 10 to 30 merozoites, which were short and thick in small schizonts while slender and long in larger schizonts. Gametocytes developed in mature erythrocytes and displayed morphologic and morphometric characters that distinguished them from other species described. Syzygy and gamete formation occurred in the gut of a leech, Johanssonia sp. Each microgametocyte produced up to 4 apparently nonflagellated gametes. Oocysts developed intracellularly in the epithelial wall of the intestine and at maturity produced under 100 sporozoites from (apparently) several germinal centers. Sporozoites subsequently migrated to the probosces of the leeches. The failure to transmit the parasite to a sculpin (Myoxocephalus octodecemspinosus) and 3 Atlantic cod (Gadus morhua) via regurgitation by the leeches might be indicative of host specificity.