GENUS DENDROSOMA. 843 



and branches, to which he assigns the distinct characters of ovaries and testes, and 

 in connection with which he maintains he observed the development respectively of 

 ova and spermatic elements. His statement with reference to this phenomenon is of 

 such importance that it is herewith reproduced. After describing the ciliated 

 embryos he thus proceeds : " The same group of organisms which had now been 

 under frequent and sometimes protracted observation for eight weeks, furnished me 

 with two specimens, showing what were evidently true sperm and germ elements, 

 these features occurring in two separate individuals in close proximity to each other. 

 They bore so much resemblance to the testis 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 Acinetina. 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. At the same time the 

 ovary on the other individual, which at first showed only a slight circular mark, had 

 now a decided opening ; though I could not positively trace the contact of the 

 fertilizing agents with the germ, the process was so conclusive as to leave no doubt 

 of its meaning in my mind." Mr. Levick further records the observation of egg-like 

 bodies, apparently derived through the union of these elements, they having some 

 resemblance to minute statoblasts of a fresh-water Polyzoon and probably remaining 

 in a like manner in a state of rest through the winter. 



Should Mr. Levick's observations concerning the reproduction of Dendrosoma 

 radians by a distinct genetic process be confirmed by further investigation he will 

 undoubtedly have made one of the most important discoveries yet recorded in 

 connection with the Infusorial series. In none of these so far is the development of 

 distinct sexual elements and the production of embryos through the concourse of 

 these elements known to occur, and should such phenomena actually take place, it 

 affords more substantial evidence than any yet adduced with reference to the 

 relatively high organization of the Acinetidae advocated in this treatise. Concerning 

 the reproduction of Dendrosoma by two independent germinal processes, the author 

 is in a position to entirely confirm the observations of Mr. Levick, though he cannot 

 proceed so far with relation to its accredited development of distinct sexual elements. 

 On many occasions within the past few years the author has had an opportunity of 

 examining examples of the type now under discussion, but it is only in connection 

 with specimens remitted from Birmingham by Mr. Thomas Bolton so recently as 

 December 1881, that the phenomena referred to have been observed. Unfortunately, 

 not being aware at the time of the nature of Mr. Levick's evidence, the opportunity 

 was lost for effecting, in connection with living specimens, an investigation of that 

 specially important point to which attention has just been drawn, though, on the 

 other hand, the results obtained have the advantage of being arrived at independently, 

 while in addition, with the use of reagents, examples, in which all of the more 

 important features as hereafter described, have been permanently preserved. 



The example of Dendrosoma radians delineated at PI. XLVII. Fig. 17 has 

 been specially selected by the author from among the specimens recently remitted 

 by Mr. Thomas Bolton, on account not only of its containing both of the two sorts of 

 reproductive bodies produced, but also as representing the largest and most extensive 

 colony-stock of which an account has so far been published. The one of very con- 

 siderable size originally figured by Claparede and Lachmann, and hitherto acknow- 

 ledged to be the largest recorded example, exhibited a total altitude of as much as one 

 millimetre (i-25th of an English inch). In the example here delineated the height of 

 the main trunk measured no less than i-ioth of an inch, with a lateral extension 

 of equal measurement, and was distinctly visible to the unaided vision. The 

 creeping stolon, not figured or referred to in Mr. Levick's description, and not 

 observable in young colony-stocks, was very extensively developed. It had a more 

 depressed form than is indicated in Claparede and Lachmann's figure, and distinctly 

 anastomosed, leaving a central perforation, wherever it came in contact with a neigh- 

 bouring outgrowth of the same element. By treating examples with osmic acid and 



