WESTON. ON THE ACTINOPHRYS SOL. 119 



by the outer membrane, previous to being drawn into the body 

 as food. Power used l-8th objective, No. 1 eje-piece. 



Fig. 3 is my best drawing with the camera lucida ; which, bad 

 as it is, will, I hope, show, a, a, two Vorticellae enclosed within 

 the vesicle. To obtain this, with mj untrained manij>ulation 

 of the camera, I had to raise the stand of the microscope a 

 foot from the table. The power used was 2-3rds objective, 

 and No. 2 eye-piece. A very few minutes sufficed to engulph 

 these larger morsels. 



With regard to the reproduction of the species, I can posi- 

 tively affirm that self-division is one mode, for I may say I 

 have witnessed it a hundred times, and shown it to others. 

 The first time it came under my observation was late in the 

 afternoon, early in the month of August last ; division had 

 commenced before the object came into view, but in less than 

 an hour it was complete. The observing of this act by a 

 more experienced microscopist than myself would, I have 

 little doubt, set at rest the question as to whether or no the 

 envelope of the Actinoplirys Sol was cellular. I watched this 

 division proceed, as in fig. 4, which was sketched about half 

 an hour after first seen. First was noticed a deep depression 

 above and below, not far from the centre of the body ; this, as 

 it increased, threw the tentacles across each other, in a manner 

 similar to that described by Kolliker, when in the act of en- 

 closing an object of prey ; this crossing, however, in the act of 

 self-division would appear to be only the necessary consequence 

 of the depressions alluded to in the sketch, and the position 

 into which the outer membrane (in which the tentacles are 

 inserted) is drawn. As division proceeded, the two animal- 

 cules steadily, but rather quickly, increased the distance 

 between them, until the connecting medium w'as apparently a 

 long membranous neck, which, to my unpractised eye, ap- 

 peared composed first of four, tlien three, then two, irregular 

 lines of cells (possessing no nuclei), which ultimately dimi- 

 nished into a single cord, comj)osed of three simple cells, 

 elongated like the links of a chain, this becoming gradually 

 more attenuated, until the exact moment of its division could 

 not be seen. All this latter portion of the process was rather 

 rapidly performed, that is, from the first formation of the rows 

 of cells, to the time of what I supposed to be the final separa- 

 tion, occupied only about a cjuarter of an hour. 



At this time only the margin of each Actinopin^ys was left 

 in the field, so rapidly had they receded from each other ; so 

 that, to watch further, I had to shift from one to the other ; 

 this, however, could only be done for a very short time, as they 

 got out of an easy line of observation, which made it necessary 



