1881.] 



MICEOSCOPICAL JOURNAL. 



185 



its power to take hold, and whilst 

 the general activity of the body 

 was convulsively increased rather 

 than lessened, its tail constantly 

 slipped back and a rapid series of 

 doublings of the body gave it no 

 headway. If it happened to get be- 

 yond the rays, it recovered its normal 

 motions in a few moments. A ChcB- 

 tonotus lams, swimming with its pecu- 

 liarly strong and graceful motion, 

 struck the rays, and the hinder half 

 of the body became instantly limp 

 and helpless, being utterly without 

 power of motion. The rest of the 

 body seemed strong as usual, and 

 kept up the most violent contortions. 

 In this case, also, if the animalcule 

 got away, its powers were restored in 

 a few moments. Another very strikmg 

 instance was that of the Trachelocerca 

 olor. Swimming with its enormously 

 long and swan-like neck extended, it 

 struck one of the rays near the head. 

 The head and part of the neck shrunk 

 like wax melted in a flame, so 

 complete and instantaneous was the 

 shrivelling and loss of form. Cases 

 of similar kinds were constantly 

 occurring, and as the animalcules 

 named are usually larger than the 

 Actinophrys, the phenomena impress 

 the observer with the extraordinary 

 power exerted. 



Conjugation. — The phenomena 

 of conjugation may be considered 

 either as to the exterior form or as to 

 the results. First, as to form. Two indi- 

 viduals approach each other by a slow, 

 sailing motion, as if merely drifting. 

 Sometimes this continues till the rays 

 having crossed each other, the bodies 



come in contact and coalesce by the 

 same imperceptibly progressive move- 

 ment. At other times amoeboid pseu- 

 dopodia are put forth before the con- 

 tact, and one or more narrow necks 

 connect the two spheres while they 

 are yet separated from each other by 

 one-sixth their diameter. 



Usually the union proceeds through 

 a dumb-bell shape till the diameter of 

 the connecting part is about two- 

 thirds that of the lobes. In a period 

 varying from a quarter of an hour to 

 several hours the separation begins, 

 the process being now reversed, 

 the Actinojjhryes stretching apart till 

 they are connected by a thread almost 

 as fine as the rays. This breaks, part 

 of the thread is absorbed by each, 

 and the two are once more completely 

 distinct. During this process the 

 rays of each lobe radiate from its 

 own centre, and the faint central 

 ring continues visible in each. 



Claparede and Lachmann speak of 

 a conjugation of three Actinophryes 

 being observed at once. Leidy men- 

 tions it also. In my notes of the 

 series of observation now related, 

 this complex conjugation has oc- 

 curred between five and six speci- 

 mens, and in one instance nine were 

 involved, though in this last they did 

 not form one complex mass. A brief 

 description of a few of these cases 

 may be instructive. 



Case I. — Nine Actinophryes were 

 observed grouped near each other, and 

 when first seen three (Fig. 34, a, b, c) 

 were in conjugation in one group, 

 two more (^, e) in another, two 

 more (/, g) in a third, and two 



Fig. 34. 



