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146 Mil. BEBKilETf 6iT THE MIOROQONIDIA OF FBESHWATEB ALGJB. 



processes in Vaucheria. He has not, however, witnessed the pro- 

 duction of spermatozoids from them. After the rupture of the 

 spore-cells has taken place, the concentrated mass soon acquires 

 an external membrane, exactly after the fashion of the spores in 

 Vaucheria, and is in a condition to be separated at the proper 

 time from the parent plant, to germinate, or to imdergo farther 

 changes instead of immediate germination. One of these bodies 

 is figured by Thuret under (Edogonittm, but he does not call any 

 particular attention to them, nor does he seem to have observed 

 them in situ. 



After reading the paper of Pringsheim, I referred to a file of 

 letters received some ten years since from Mr. Thwaites, and 

 under the date of Apr8 1846 1 found a correct figure of the micro- 

 gonidia in a species of (Edoffonium, agreeing exactly with the ac- 

 count of Pringsheim, as does a inoimted specimen received at the 

 same time which is still in excellent condition. Mr. Thwaites 

 remarks that these bodies appear to be of the same nature with 

 the horns in Vaucheria, and that they are probably antheridia ; 

 but he was led aside from following the clue before him by theo- 

 retical views which in the end proved of far less importance. It 

 is curious that he had not observed them also in Bulbochate, for 

 moimted specimens received from him about the same time exhibit 

 them in great abundance. Mr. Broome, who was at that time the 

 constant companion of Mr. Thwaites in his scientific pursuits, has 

 at my request examined his own moimted specimens of Bulhochete. 

 He finds that microgonidia are equally abundant in them as in my 

 own specimens, and has moreover transmitted sketches, which are 

 now laid before the Society. There is no doubt that Pringsheim 

 will follow up the question which he has so successfully begun ; 

 but as the season is just at hand for observing these bodies in per- 

 fection, I have thought that an especial notice of their observation 

 some years since in England might be interesting to sucTi Members 

 as may not have met with Pringsheim*s memoir. 



The same author has, moreover, made some important dis- 

 coveries as to the development of the sJ)ore in Bulhoclu^e after 

 separation from the mother-cell. The spore, after remaining Some 

 weeks without much alteration, at length escapes, and in a few 

 hours elongates, attaining twice its original length. The endo- 

 chrome Tby successive division gives rise to four distinct bodies 

 which acquire a nearly globular form aiid are furnished at one ex- 

 tremity 'with two sets of ciliary processes, by means of which they 

 move about, aind thus appear in the condition of zoospores. >J*7* 



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