DENDROSOMA RADIANS. 



multiplication in the Acineta, namely, by free embryos, ■which at this 

 stage were supposed by some observers to pass into their "perfect" condi- 

 tions as Vorticellee, Vaginicolae, <fec., though the "perfect" condition of 

 Dendrosoma in particular seems not to have been fixed upon. 



In the adult form I have not positively recognised a nucleus, being 

 unable to treat my specimens with reagents, as I could not separate the 

 gi"oup under observation without spoiling it, but in the free embryos what 

 at first appeared as a second vesicle proved to be a nucleus and nucleolus, 

 (Fig 4Ba.) 



A curious feature of these free ciliated embryos was that, after 

 swimming about in a purposeless manner for a time, they settled down, 

 attaching themselves to anything near ; the cilia then gave place to 

 pseudopodia, much like those of an Actinophrys, which in the one 

 sketched at Fig. C wei-e ranged neai'ly at a tangent. This embryo (Fig. 46) 

 anchored itself to a diatom equal in length to its own diameter, and 

 afterwards ingested it as an Actinophrys or Amoeba would. Figs. 4E and 

 4F show the gradual return of the parent Dendrosoma to the normal form, 

 after the escape of the embryo. 



It is somewhat singular that, though conjugation is set down by one 

 or two observers as common in the Acinetae, I have never seen it, 

 although I have made special search for it ; but in two Dendi-osomata I 

 saw what may possibly have been an attempt in that direction, when 

 they evidently modified their shape for some purpose or other, though in 

 such a manner that I could not decide whether one was merely moving 

 out of the way of the other, or trying to swallow it. 



The same group of specimens which had now been under frequent 

 and sometimes protracted observation for eight weeks furnished me 

 with two specimens, showing what were evidently the true sperm and 

 germ elements, these features occurring on two separate individuals in 

 close proximity to each other, (Figs. 3c, 5a.) They bore so much resem- 

 blance to the testes and ovary of the Hydra that I felt no doubt whatever 

 of their function from the first, though I had never seen the phenomenon 

 before in Dendrosoma, and was not aware of its having been noted in 

 this or any other form of the Acinetiua. After a little patient watching, 

 I was rewarded by seeing the spermatozoa, not only in active motion 

 within the sperm cell, but also escaping freely into the surrounding 

 water, (Fig. 3c.) At the same time the ovary on the other individual, 

 which at first showed only a slight circular mark, had now a decided 

 opening, (Fig. oa ;) though I could not positively trace the contact of the 

 fertihsiug agents with the germ, the process was so conclusive as to leave 

 no doubt of its meaning on my mind. 



I was now anxious to discover, if possible, the result of this 

 phenomenon ; and, having become so famihar with Dendrosoma in a 

 great variety of forms, and my specimens being isolated, I had not 

 much difficulty in recognising the form sketched in Fig. 4G as the 

 probable egg. The before-mentioned embryos and this germ had 

 the same histological characters as well as the common distin- 



