398 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



Hereditary Rickettsia-like Parasite of Bed-bug. — J. A. Ark- 

 WRiGHT, E. E. Atkix, and A. Bacot {Parasltologtj, l'.)21, 13, 27-3n, 

 2 pis., 1 fig.). The organism called " Rickettsia " are like very small 

 bacteria, but not motile and otherwise peculiar. They occur in very 

 large numbers in the gut and in some cases in other organs of blood- 

 sucking insects and in ticks. The supposed cause of typhus fever is 

 Rkkettsia prowazeki found in the louse. In the case of the bed-bug it 

 seems that the organism occurs in the undifferentiated egg mass, and 

 is thus continued from generation to generation. It is suggested that 

 they change from the form of minute granules to a long bacillary form 

 in suitable places such as the large cells of the Malpighian tubes of the 

 bed-bug, and that the long threads in turn release minute bodies. 



J. A. T. 



Structure of Cnidosporidian Spores. — R. Kudo (Trans. Amer. 

 Micr. Soc, 1921, 40, 51)-7-4). Discussion of structures characteristic 

 of cnidosporidian spores. The spore membrane of Nosema apis and N. 

 bombycis, taken as representative of the Microsporidia, is proved to be 

 composed of a substance similar to chitin in its chemical reaction. 

 The spore membrane of Henneguya saJminirola, taken as a representa- 

 tive of the Myxosporidia, is not so like chitin. The polar filaments of 

 cnidosporidian spores are not composed of glycogen as was suggested 

 by Erdmann. They consist of a mixture of a part of the nucleus and 

 a substance diflferentiated in the capsillogenous cell. There follows a 

 discussion of the methods which cause extrusion of the filament. The 

 so-called iodinophilous vacuole of the spores of the family Myxobolid® 

 contains a substance like glycogen in its reactions. J. A. T. 



Fish Myxosporidia. — J. S. Dunkerly (ParasiMoyy, 1920, 12, 

 ;^28-88, 6 figs.). Descriptions of Geratomyxa lata sp. n. from Gapros 

 sanglier, G. duhia from Coftiis bubalis, Myxidium iiiler medium sp. n, 

 from Pleurone'ies flesus, Sphseromyxa long a sp. n. from Oadus minvtus, 

 and S. ovata sp n. from Onos tricirratus. Reports of other Myxo- 

 sporidia, not new species, from many other hosts. J. A. T. 



