106 JAMES FULLAGAR ON THE 



of eight which had thus become amalgamated, from which state I 

 witnessed their separation and the various changes that followed. 

 I have given an illustration of one only, though the whole of the 

 group underwent the same changes to the time when they arrived 

 at the stage shown in Fig. 6. Figs. 7, 8, and 9 show the varied 

 appearances of the same objects under a ^-inch objective ; that at 

 Fig. 9 has a peculiar reticulated appearance. (Plates VII. VIII.) 

 When thus joined together in a mass, they are capable of 

 seizing and retaining, by their united efforts, large animalcules. I 

 have seen three large Paramecin enclosed at one time, and each of 

 them in a separate circle, from which nutriment appears to be ex- 

 tracted and diffused through the whole number thus united in one 

 body. They feed voraciously at this time — namely, just before 

 their encystment commences, for which, I think, this fusion of 

 many together to be preparatory. When fully fed, they again 

 divide into their individual forms in the same gradual manner as in 

 the act of fission. When completely separated, the spines are of an 

 extraordinary length, some of them being twice the diameter of the 

 body in length, and very brilliant ; as they separate, they move a 

 short distance from each other, so that the spines are quite clear 

 of one another, and then remain stationary, preparatory to the next 

 change. And now the spines begin to shorten by being slowly 

 withdrawn into the body, and in about four hours they so far dis- 

 appear as to present the appearance as shown in Fig. 1 ; in about 

 two hours more they are entirely withdrawn (Fig. 2). As the 

 spines shorten, the centre of the body is observed to become darker. 

 The contractile vescicle (Fig. 2. a) continues to act for a short time 

 after the spines have disappeared. But soon another change takes 

 place in the interior, the contents of which, in about six hours, are 

 found to be divided into two equal- sized globes, still surrounded by 

 the original circle (Fig. 3. a), at which time a very transparent film 

 is seen to be thrown out which entirely surrounds it (Fig. 3. b) . 

 These globes, in about twelve hours, gradually change into the 

 form shown at Fig. 4, when the original circle loses its roundness 

 (Fig. 4. c) , and finally disappears, and they continue to alter in 

 shape, until the two bodies take the form shown at Fig. 5, in which 

 state the dark parts continue quite separate from each other, so 

 that a space can be seen between them. They remain for some hours 

 in this position, when they approach each other, and a union again 

 takes place, commencing in the centre (Fig. 5) ; and in the course 



