ARCHER AND DIXON, ON DESMIDIACE./E. 89 



Spirogyra, and which, as here, not being the result of con- 

 jugation, are formed by either a portion or the whole of the 

 green contents of a single joint being absorbed in their pro- 

 duction, and are spherical and spinous. My friend, Mr. 

 Edward Crowe, lately showed me specimens of Zygnema, in 

 which the entire cell-contents of many joints of the fila- 

 ments had become consolidated into a globose or somewhat 

 pear-shaped and smooth spore-like body, which, by expansion 

 in one direction towards one side, eventually burst through 

 the boundary-wall, emerging into the surrounding water by 

 the rupture thus effected. Mr. Crowe informs me that he 

 was not able to trace their ultimate destiny, as they indeed 

 perished before undergoing any further development. It is 

 probable that these bodies, both in the Desmidians to which 

 I have above alluded, as well as the similar productions in 

 the above-mentioned Zygnemaca?, in each case formed with- 

 out conjugation, are Gonidia, by which the organisms may 

 be severally propagated. — It may not be out of place to men- 

 tion here that I have several times noticed in Closterium 

 lunula the entire cell-contents transformed into a dense longi- 

 tudinal series of flask-shaped bodies, with their narrow necks 

 projecting to the outer wall, precisely similar to those figured 

 by Carter (' Annals of Natural History/ 2d series, vol. 

 xvii, p. 114, pi. ix, fig. 9), as occurring in Spirogyra, also 

 by Henfrey (' Quart. Journ. Mic. Sci./ vol. vii, p. 27, 

 pi. iii, fig. 12), as occurring in his Chlorospkcera Oliveri, 

 equivalent, I think, to Eremosphcera viridis (tie Bary) ; and 

 I imagine also the same as the unicellular alga mentioned by 

 Hofmeister in his paper ' On the Reproduction of the Des- 

 midise and Diatoniese/ translated in ' Annals of Natural 

 History' (vol. i, 3d series, p. 1, January, 1858). In my 

 specimens of Closterium lunula alluded to, the longitudinal 

 mass of these flask-shaped bodies more than once has sug- 

 gested to me the hanks of onions as seen hanging up in the 

 market. I have never seen them, however, to produce what 

 Professor Henfrey considered the spermatozoids in his 

 Chlorosphsera, which plant, as I have before elsewhere stated 

 (' Natural History Review/ vol. v, p. 258), though then 

 without knowing that De Bary and Henfrey had named it, is 

 of common occurrence in our district. — Another curious 

 growth in the interior of Closterium lunula I would just 

 notice. I refer to the production, within the otherwise empty 

 frond, of a slender jointed filament, contorted and twisted in 

 every direction, and occasionally inosculating; the joints 

 without any apparent contents, save a very few green granules, 

 .scattered at considerable intervals. This I should imagine a 



