OF THE TOLYOCINA. 521 



lope"). Clusters of these beautiful ani- 

 malcules are often seen in such amazing 

 numbers, along with the Vohox Glohator 



tempted to retain them in large quanti- 

 ties, the second day wall generally ex- 

 hibit a thick mass of dead ones at the 



and Chlamydomonas Pulvisculus, as to j bottom of the vessel. When a few 

 render the water (otherwise colourless) ; only remain alive, if the stale water 

 of a decided green colom*, especially j be pom-ed away, and they are removed 

 towards its edges. They are exceed- ■ into a vessel of clear water, they will 

 ingly delicate — so much so that it is j live for weeks. At Hackney and Hamp- 

 ditficult to preserve them alive for more stead ; most abimdant in the spring of 

 than a day or two : whenever it is at- ' the year. Diam. of cluster 1-180". 



Genus CHLAMYDOMONAS (XYIII. 40, 51-54; XIX. 16) (Part T. 

 p. 146). — Tail absent, eye-speck distinct red, filament double ; multiplication 

 takes i^laee by self- division within the common envelope, which is ruptui-ed 

 to give the products liberty. The lorica indistinct in young beings. 



Braun {On Rejuvenescence, Ray Soc. 1853, p. 158) appears to elevate this 

 genus, in union with Chlamydococcus and Gloeococciis, to the rank of a family 

 parallel mth the Yolvocina, under the name of ChJamydomonada. Indeed, 

 although, as Cohn has weU shown, these genera agree in aU essential particu- 

 lars and relations with the Yolvocina, yet the existence of each gonidium 

 as an independent being contrasts so strongly mth the aggregate condition 

 of the rest of the Yolvocina, that there seems sufficient ground to group them 

 as a sub-family. In order, therefore, to retain the Chlamydomonada toge- 

 ther, we shall depart from our usual custom, by inserting the new genera 

 Chlamydococcus and Gloeococcus after Chlamydomonas. Chlamydomonas was 

 erroneously transferred, as before noticed, by Dujardin to the Thecamonadina, 

 and renamed Diselmis. Its characters are thus discussed by Braun (oj). cit. 

 pp. 214, 215) : — " CJiJamydomonas is distinguished from the genus Chlamydo- 

 coccus by the closely applied membrane of the old swarming-ceUs, also by the 

 absence of the little starch-vesicles ui the interior, while, however, as is 

 usual in most of the Palmellaceae, a single large chlorophyll utricle exists in 

 the iaterior. There is no central red nucleus, as in the gonidia of CJdamy- 

 dococcus ; but some species have a parietal red spot. Motion is effected 

 by two cilia, as in Chlamydococcus. As in that genus, there is a growth of 

 the gonidia during swarming, which lasts over the day and night. There is 

 also a formation of microgonidia," and a resting-stage m which the colour 

 changes from green to yellowish red, or to red. 



Chlamydomonas Pukiscidus {Manas 

 Pidviscuhis, M.)(xix. 16). — Colour green ; 

 lorica oval ; eye-speck brilliant red ; fila- 

 ment double. (See Diselmis viridis, 

 p. 512.) Cohn identifies it -with Pol ytoma 

 Uvella. 



These creatures form a large portion 

 of the gTeen matter which colom-s the 

 water contained in water-butts, ponds 

 and puddles in the summer and autumn, 

 and especially after a storm. They will 

 rarely fail to be obseiwed when any of 



this gTeen water is examined imder the 

 microscope. Whenever these creatures 

 exist in large quantities, midtitudes of 

 them and of their envelopes rise to the 

 surface of the water, and form a gi-een 

 stratmn upon it. Although this film 

 somewhat resembles one of Ulvaceae, yet 

 it is easUy distinguishable by its com- 

 position of living coi*puscles with red 

 specks, connected together by a loose 

 mucous tissue, formed of dead speci- 

 mens and empty loricae. 1-550". 



Kiitzing affirmed that this species was merely a phase of Stygcoclinium, into 

 the filaments of which it became transformed by an act of germination. This 

 opinion has not been accepted, as it is supposed that Kiitzuig confounded the 

 spores of that Alga vdih. the gonidia of Chlamydomonas Pidviscidus. 



Among the additional species of Chlamydomonas, those forms described by 

 Dujardin as members of Diselmis (p. 512) should probably take their place 



