Some New Gregarine Parasites from Arthropoda

For several years I have been studying a number of gregarines parasitic in various arthropods.The literature apparently contains no record of most of them and consequently they are here described as new species.A few of the species studied were already known, but I am able to give new records on distribution and additional data on biology and life-history.Careful attention was devoted to the biology of the forms studied and extended experiments were conducted on life-history problems.In this paper is presented a brief account of these studies, which will be published in full at a later date.Especial attention is called here to the observations on movement in gregarines and on cyst formation.The descriptions of new species though concise have been worked over so carefully that it is thought they will be ample for accurate determinations. BIOLOGICAL OBSERVATIONSThe polycystid gregarines have a septum which divides the cell into two or more distinct compartments, and the species described in this paper are all of this type.Polycystid gregarines inhabit chiefly the mid-intestines and intestinal diverticula of arthropods and are often found in large masses comprising many hundred parasites.In some genera the adult animals are solitary ; in others they are attached one behind the other.Most of the latter are biassociative, but a few genera occur in chains of from three to ten or twelve individuals.The sporonts, or adult animals, move about freely in the lumen of the intestines or lie inert between the lobes.The trophozoites, or young individuals, live either entirely within the epithelial cells, as in the family Stenophoridae, or attached to the free ends of the cells by means of variously shaped epimerites, globular in the genus Gregarina.When a trophozoite has absorbed sufficient nourishment from the host cell, either directly through its walls or by means of the epimerite, it breaks forth from the shriveled cell and becomes a sporont, living free in the intestine, and the useless epimerite, if present, is gradually lost.The animal now receives its food entirely by absorption of the digestive juices direct from the host intestine.