THE BEGINNINGS OF LIFE. 179 



Zygnemaceg originate in the same way as those of (Edo- 

 gonmm^ with the single distinction that in the former 

 the contents of two chambers become united to form 

 one seed-cell.' 



A mode of production of zoospores different from 

 that already described by Agardh, and resembling more 

 closely that by which the seed-spore of (Edogonlum is 

 produced, is now known to take place in Achlya pro- 

 Hfera a curious little plant first discovered by Prof. 

 Goodsir, on the gills of certain gold fish which were in 

 an unhealthy condition. It was formerly thought to be 

 a species of Conferva, but it is now regarded by the 

 Rev. M. J. Berkeley and others as merely a submerged 

 or aquatic form of a Mucor. This, as one of the simplest 

 kinds of Fungi, has been made the subject of a most 

 careful investigation by Prof. Unger J . When in the 



beginning of the combination, the cells are filled with finely granular 

 contents, in which we see arise, during the progress of the union, shining 

 drops, at first very small and distant, gradually growing larger, coming 

 in contact and coalescing, so that the intermediate contents almost en- 

 tirely disappear, and the complete spore appears filled merely with a 

 mixture of oil drops of the most varied size. During this process the 

 colour of the cells changes from green to a light yellowish brown. 

 Vegetative cells with homogeneous green contents originate subse- 

 quently through transformation and division of the contents of these 

 oleaginous seed-cells.' (Loc. cit. p. 202, and PI. I, II.) In connection 

 with this subject, also, we may call attention to the fact elsewhere 

 (Linn. Soc. Trans, xxv. 1865, p. 84) mentioned, of the large amount of 

 free fat frequently existing within the intestinal canal of many of the 

 Free Nematoids, which appears to result from the more or less direct 

 transformation of the cellulose taken as food. 



1 ' Einiges zur Lebensgeschichte der Achlya prolifera,' in ' Linnaea,' 

 1843, t. iv. 



N 2 



