OF THE VOLVOCINA. 515 



stood, and supported it on the fact that an act of germination, similar to 

 that seen among the spores of the lower Algae, was never witnessed among 

 the Yolvocina. This absence of a supposed vegetable characteristic, more 

 recent researches appear clearly to set aside as an argument against the 

 vegetable natui^e of a doubtful organism ; for in the whole cycle of life of 

 many of the simplest, or so-called unicellular plants, an act of germination, 

 as understood by Thuret, never occm's. Dujardin, when he published his 

 work on Infusoria in 1841, admitted the Volvocina among animalcules, but 

 proposed a diiferent distribution of theii' genera to that put forward by 

 Ehrenberg. Thus, he transferred Gyges and Chlamydomonas, owing to their 

 not being aggregated mthin a common envelope, to the Thecamonadina, and 

 united Eudorina with Pandorina (XIX. 59-69), and Synura T\ith Uroglena, 

 because he could not regard the presence or absence of a red speck to be a 

 generic characteristic. Fiu'ther, he considered Syncryi^ta a doubtful genus, 

 and combined Sphceroswa with Pandorina. 



Although the present state of science proves that the appearance of a red 

 speck or specks in a monadiform being is mostly a transitory phenomenon, 

 associated with a certain condition or phase of existence, and that therefore 

 the union of Eudorina with Pandorina, and of Synura with Uroglena, is a 

 correct proceeding, yet Dujardin erred both in detaching Gyges and CJdamy- 

 domonas (XIX. 16) from the Yolvocina, and in considering Sj^ha^rosira and 

 Pandorina modifications of a common form. The relation of Cidamydomonas 

 to the Yolvocina has been weU shown by Cohn, Braun, and others ; and 

 Gyges itself might probably be dispensed with as a distinct genus, since there 

 is good evidence to show that its species are simply stages of development of 

 Chlamydococcus or Protococcus (XIX. 20-31), and of Chlamydomonas. Again, 

 Sjfhcerosira, instead of being a varied phase of Pandorina, is a member of the 

 genus Volvox ; indeed Prof. Busk incHnes to the notion that it is merely a 

 developmental stage of the common Vohox GJohator (T. M. S. i. p. 39). Perty, 

 however, advances as an argument for its independent natiu-e, that it is com- 

 mon about Bern, whilst Volvox Globator is not met Avith. This fact speaks 

 at least for the specific independence of Splicer osir a, although its generic 

 must be given up. Moreover, a genus Botryocystis was instituted by Kiitzing, 

 of the independence of which, however, there is no good evidence. The con- 

 dition of Protococcus pluviaJis (Cohn, Ray Soc. 1853, p. 559), when di\ided into 

 sixteen segments, con'esponds to the Botryocystis Morum. Fiu^ther, the last- 

 cited author in another treatise (EntiuicJc. d. Mikrosl^op. Alg. und Pike, p. 209) 

 treats Botryocystis as synonymous vrith Pandorina, and in this agrees with 

 Prof. Henfrey, who remarks {M. T. 1856, p. 51) that the form of Pandorina 

 which produces the resting-spores, after losing its cilia, is Kiitzing's Botryo- 

 cystis Morum. Perty coins two new genera, called SynapTiia and Hirmidium 

 (XIX. 15). Cohn points out a natural division of the Yolvocina into two 

 sections, in the fii^st of which, represented by Chlamydomonas and Chlamy- 

 dococcus, the fission of each primordial cell is complete, and the products 

 single and unicellular, whilst in the second section, including all the rest of 

 the Yolvocina, the cells formed by the fission of the parent primordial cell con- 

 tinue united in groups or clusters. The difference between the several genera 

 obtains from the disposition of the produced eeUs ; and this, again, depends on 

 the dii-ection of the line of fission. Thus, in Stephanosphcvra (XIX. 38-52) 

 the plane of fission is the meridian of the sphere ; in Gonium it occurs in two 

 planes at right angles to each other, and in Volvo.v and its aUies in three 

 planes. If the Yolvocina are referable to the vegetable kingdom, they consti- 

 tute a family of the order Palmellaceae (Chamaephjxea?, K.), among the Algae. 

 The separation of Syncrijpta from Gyges, and its independent generic ex- 



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