OP THE PHYTOZOA. 151 



partite zoospores with the secondary cells arranged in one plane, vre have a 

 Gonium. That with eight segments corresponds to Pandorina Monim, and 

 that with sixteen to Botnjocijstis Volvox. When the zoospore is divided into 

 thirty- two segments, it is a Uvella or Sijncrypta (XIX. 27). When this 

 form enters the ' still ' stage, it may be regarded as a form analogous to 

 Microhcdoa protogenita ; this Algal genus is probably, speaking generally, 

 only the product of the ?7i'e??« -division in the Eughnce or other green forms. 

 The naked zoospores (XIX. 28), finally, would represent the form of a 

 Monad or of an Astasia (XIX. 29) ; the caudate variety approaches that of 

 a BodoJ' 



Perty has devoted several pages to recount his own obsei-vations and ex- 

 periments on the genus CJdamydococcus, or, as he prefers to call it, Hysgi- 

 num. He institutes two species, which he states to be equivalent to Proto- 

 coceus ]yluvialis and P. nivalis of other authors, and insists on their specific 

 distinctness. Probably, he adds, other varieties of Protococcus coloiu'ed red 

 are also referable to this genus, at least such of them as present an animal 

 phase of existence. To his mind, the vital phenomena of such organisms 

 are best explicable on the supposition of an animal nature ; for, says he, 

 cells which move altogether like Infusoria, and exhibit sensation in their 

 yoimg conchtion, so long as they j)resent such phenomena, are not vegetable 

 cells. Moreover, he thinks it established concerning the Phytozoa in general, 

 that in certain stages of their life they sometimes belong to one, and in 

 others to another kingdom of nature, or are so nearly allied to both that a 

 separation is impossible. 



After the space akeady devoted to the structure of Chlamydomonas and 

 Chlamydococcus, an abstract of Perty's long contribution on the subject can- 

 not be introduced ; and indeed, apart from his diiferent interpretation of 

 their vital phenomena, little could be produced not included in Cohn's com- 

 plete examination. There is, however, a paragraph in Mr. Carter's just 

 published valuable contribution on Eudoyina, referring to Chlamydococcus, 

 which must not be omitted. He writes {A. N. H. 1858, ii. 244) : " Chlamy- 

 dococcus undergoes the same kind of changes in development as Eudorina, 

 from which it only differs in structiu-e in being smaller and globular instead 

 of ovoid, in the absence of an external envelope, and in the ciha of the 

 daughter- cells being included within the parent-cell ; hence it also difi'ers in 

 being motionless, though the compartments of the daughter- cells are suffi- 

 ciently large for them to tiu-n round and move their cilia freely therein, 

 which they are continually doing. The primary cell of Chlamydococcus, like 

 that of Eudorina, divides up into two, four, eight, or sixteen cells, and those 

 of the eight- and sixteen-di\-isions again into groups of sixteen or thirty-two 

 each, so as to resemble the thii^d stage of Eudorhia. Hence we may perhaps 

 infer that its fecundating process is similar to that of Eudorina ; but this 

 remains to be discovered. Chlamydococcus has also a great tendency to stop 

 at the two- and four-division, from which it may pass into the ' stilL ' or 

 Protococcus-f orm., and, floating on the water in a kind of crust, present ceUs 

 of all kinds of sizes undergoing ' still' division. "In aU its multiplications, 

 partial and entire, however, it generally maintains its primary or spherical 

 foiTu, and does not become ovoid or oblong like the groups of Eudorina, — the 

 only exceptions being in the two- and four-division, where the green cells 

 are sometimes ovate (probably from want of room in the parent capsule), as 

 represented by Ehrenberg in C. Pulvisculus, to which I should refer it, had 

 he not also given an ovate form to the type-cell of this species : nor can I 

 refer it to C. pluvialis ; for in all the changes I have yet seen it undergo, the 

 red colour has not increased beyond the minute eye-spot, while this also dis- 



