770 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Karyokiuetic changes in the nucleus were observed. The division of the 

 nucleolus, the formation of nuclear asters, the complete fusion of the 

 conjugating individual, the expulsion of polar elements, and the formation 

 of a new nucleus, which undergoes the subsequent division, are described 

 in the original Hungarian paper. 



Spore-formation in Gregarines.* — M. L. F. Henneguy reports the results 

 of his application of modern technical methods to the elucidation of spore- 

 formation in Monocystis agilis of the earthworm. It has been observed by 

 Lieberkiihn, for instance, that the spores may arise in different ways. 

 Sometimes the cyst becomes covered with small clear vesicles which develope 

 into pseudo-navicellae ; sometimes the contents segment like an ovum ; some- 

 times the mass divides into a number of smaller masses, each of which 

 becomes covered with spores. It is also known that the spores inclose a 

 nucleus, and divide into several falciform nucleated elements surrounding a 

 central residual core — the noyau de reliquat. A. Schneider has further 

 described the repeated division of the nucleus and the distribution of the 

 results throughout the protoplasm. 



M. Henneguy's results corroborate those of Schneider, of which the author 

 was unaware when he began his researches. By means of sections, &c., 

 the following points have been demonstrated. (1) First of all, vacuoles 

 appear in the large nucleolus ; this breaks up into fragments ; and a true 

 karyokinetic division of the nucleus occurs. (2) If the contents of the 

 cyst do not also divide, and the nuclei continue to multiply by division, 

 they migrate to the surface, and there become surrounded by a little 

 protoplasm. They do not all move outwards, however, to form a surface 

 layer. A certain number remain at the centre, and there degenerate. 

 (3) "When the contents of the cyst divide into a few large masses, the same 

 formation of spores is exhibited. The nuclei of each mass multiply by 

 karyokinesis, and move to the surface. 



M. Henneguy never observed the third mode of spore-formation 

 described by Lieberkiihn, where the whole cyst segments into spores. A 

 central core is always to be seen at a given stage. The above facts 

 apply to the macrosj^ores, but within the microspore cysts the same processes 

 were observed. The latter divide into a larger number of masses than the 

 macrospore cysts. The author noted the presence of at least two distinct 

 species — Monocystis agilis and M. magna. In some cases M. agilis was 

 alone present, and with it were associated only microspore cysts. 



Both macro- and microspores inclose a large nucleus with a chromatic 

 network. The nucleus divides by karyokinesis, and as in the case of the 

 cysts the equatorial plate and the " pectiniform " figure were observed. 

 Each daughter nucleus retires to an opposite pole and there undergoes two 

 successive divisions. The results move to the centre and become surrounded 

 by protoplasm, forming eight units round the residual core of Schneider. 

 The general occurrence of indirect division is thus once more 

 demonstrated. 



Revision of the Microsporidia.f — M. E. Moniez has some notes pre- 

 paratory to revision of the Microsporidia. He describes a species, Nosema 

 helminthorum, which lives in unarmed Tsenise ; the same or a closely allied 

 form has been seen in Ascaris mystax. Nosema anomala is j^robably wrongly 

 placed among the Microsporidia, as its spores are very small, have no 

 suture, or geminate vesicles. The species found by Ylacovich in Coluber 

 carhonarius is called Nosema heteroica. In Cyclops two species — N. parva 



* GK. Soo. Biol, 1887, 4 pp. t Gomptes Eendus, civ. (1887) pp. 1312-4 



