SPOROZOA, GREGARINIDA 457 



P. gigantea (van Beneden) (Fig. 211, a-f). Sporadins in Ho- 

 marus gammarus, up to 10 mm. long; cysts 3-4 mm. in diameter; 

 gymnospores spherical, 8/x in diameter (Hatt), containing some 

 1500 merozoites; in molluscan hosts, Mytilus minimus and Tro- 

 chocochlea mutahilis, they develop into naked sporozoites (17/i long) 

 which are usually grouped within phagocytes. 



Genus Nematopsis Schneider. Development similar to that of 

 Porospora (Hatt) ; but each sporozoite in a double envelope. 



N. legeri (de Beauchamp) {Porospora galloprovincialis Leger and 

 Duboscq; N. ostrearum Prytherch) (Fig. 211, g-n). Hatt (1931) 

 carried on a very careful study of its development. Sporadins in a 

 crustacean, Eriphia spiniffons, in linear or bifurcated syzygy 

 75-750/x long; cysts about 80/x in diameter; gymnospores 7m in 

 diameter, composed of fewer, but larger merozoites; permanent 

 spores with a distinct one-piece shell (endospore) and a less con- 

 spicuous epispore, about 14-15)U long and circular in cross-section, 

 develop in numerous species of molluscan hosts: Mytilus gallo- 

 provincialis, M. minimus, Lasea rubra, Cardita calyculata, Chiton 

 caprearum, Trochocochlea turbinata, T. articulata, T. mutabilis, 

 Phorcus richardi, Gibbula divaricata, G. rarilineata, G. adamsoni, 

 Pisania maculosa, Cerithium rupestre, Columbella rustica, and 

 Conus mediterraneus in European waters. 



The author found in Oslrea virginica and other molluscs in 

 North Carolina, Virginia, and Maryland, this gregarine and was 

 the first to demonstrate on this continent the germination of the 

 spores taken from the infected oysters in the stomach and midgut 

 of Panopeus herbsti and Eurypanopeus depressus at the Bureau 

 of Fisheries Biological Laboratory at Beaufort, N. C, in July, 

 1936. The vermiform sporozoites emerge from the spores in the 

 pyloric chamber of the stomach and more abundantly in the mid- 

 gut of the mud crabs as early as thirty minutes after introduction 

 of the infected tissues of the oyster into their mouths. In the brack- 

 ish water of the middle Chesapeake Bay region of Maryland, the 

 oyster and other molluscs are only slightly infected. The presence 

 of the characteristic spores in oyster tissues is easily demonstrated 

 by addition of 10 per cent sodium hydroxide solution to the mate- 

 rial on slides. 



Suborder 2 Schizogregarinaria Leger 



The schizogregarines are intestinal parasites of arthropods, an- 

 nelids, and tunicates. When the spore gains entrance to the di- 



