246 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the small masses, he could not detect any signs of their presence after 

 separation. For about five minutes small protoplasmic masses, 

 exhibiting distinct and independent amoeboid movements, continued 

 to be shed. 



The rocking movement still continued, but now commenced to 

 show signs of being converted into a movement of rotation. Finally, 

 a rotary motion was established, and the animal commenced to change 

 its position. At the same time was noticed a distinct elongation 

 occurring at the end where the changes described above had taken place, 

 a rounded projection appearing, which gradually elongated, until 

 finally, in the course of about two hours, the individual had assumed 

 its original shape and activity, although apparently somewhat 

 diminished in bulk. Cilia covered the new growth, but they did not 

 seem to be a new formation, but were produced by a simple elonga- 

 tion of the ectosarc, this being carried forward by the growing 

 endosarc. As regards the protoplasmic masses that were shed or 

 discharged, he observed them for about four hours, at which time 

 they were still active, and the parent mass still in active motion. On 

 the following day he was unable to detect them, and as to their 

 subsequent history knows nothing. 



To characterize the phenomena as described above, the term 

 " Eeproduction by Partial Dissociation " is proposed. Eeproduction 

 by fission, gemmation, conjugation, and encystation have all been 

 observed in the ciliated infusoria ; and some of the older writers, 

 such as Ehrenberg and others, have described a mode of increase, 

 in which the substance of the body breaks up into a number of frag- 

 ments, each of which is capable of becoming a distinct individual. 

 This process they called diffluence, but Stein and more recent observers 

 have denied the existence of this process, claiming that it was merely 

 a form of increase from encysted forms. The phenomena, as exhibited 

 by AmpMlejptus fasciola, seem to be quite different from those described 

 as occurring in diffluence, and it certainly was not a case of encys- 

 tation. Dr. Parker being unable to find any account of reproduction 

 in the Infusoria resembling that described, places the facts on record, 

 in order that the attention of other observers may be directed towards 

 the verification of the phenomena and views expressed above. 



Orders of the Radiolaria.* — E. Hackel reports that he has been 

 able to add considerably to the two thousand new species of Eadio- 

 laria which, some time since, he was able to announce that he had 

 detected "among the inconceivably rich Eadiolarian collection of 

 the ' Challenger ' collection." Increase of knowledge has led to a 

 reduction of the proposed seven orders to four, and the complicated 

 system is now " much more comprehensible " ; it now seems to be 

 certain that the distinction between the monozoic (solitary) and the 

 polyzoic (social) Eadiolaria is not so important as was once imagined, 

 and it has been found that, contrary to the opinion of Hertwig, the 

 central capsule is in all Eadiolaria uninuclear at an early and 



* SB. Jenaisch. Ges. f. Med. u. Nat., IGth Feb., 1883. Of. Nature, xxix. 

 (1884) pp. 274-6, 296-9. 



