522 



SYSTEMATIC HISTORY OP THE INFUSOBIA. 



here. Braun describes the following new species, premising the remark that 

 <' the species are doubtless very numerous, but the distinction of them from 

 one another, as well as from the swarming cells of many other Algae, is 

 very difficult mthout a complete acquaintance with the history of their 

 existence." 



C. obtusa(BvBnrL). — Colour dark green; 

 truncate at both ends, and oblong, chang- 

 ing to spherical and a yellowish brown, 

 and at length a red coloiu: on assiuning 

 the resting-stage. ''The macrogonidia 

 grow during swarming, from l-60th to 

 almost l-30th of a millimetre long ; they 

 are longish, of equal diameter on both 

 sides, and veiy obtuse, almost trimcated, 

 haying a colomiess space at the ciliated 

 extremity, presenting the form of a notch. 

 The contents are dark green, finely 

 granular, with a large vesicle at the pos- 

 terior extremity, a roundish lighter 

 space m front of this, and no red point. 

 They multiply by simple or double 

 hahing in several successive genera- 

 tions. Sometimes a further continua- 

 tion of the division of the full-grown 

 macrogonidia occm's, forming 16 or 32 

 macrogonidia from l-200th to l-120th 

 millimetre long, of ovate shape and 

 lighter colom*, tending towards brownish- 

 yellow. The resting (seed-) cells are 

 globidar, about l-40th millimetre in dia- 

 meter, at first green, subsequently light 

 yellowish-brown, finally flesh-red ; they 

 have a tough, colourless, and transpa- 

 rent membrane. In the Rhine valley, 

 near Freibiu'g, in pools in sand-pits, 

 which are occasionally almost completely 

 dried up in summer." 



C. tingens (Braun). — Gonidia smaller 

 than in the preceding species, 1-120 to 

 1-60 millim. long, ovate, lighter green, 

 likewise destitute of a red spot; the 

 membrane is more distinct in old age. 

 Increase by double, rarely by single 

 halving ; in the former case, by decussat- 

 ing sections. Contents granular, punctate 

 in appearance, green, with one large 

 vesicle. In the resting-stage they ac- 

 quire a pale reddish colom* ; the vesicle 

 becomes indistinct, and the contents 

 coarsely gi-anular in aspect fi'om the 

 formation of oil. Microgonidia also are 

 foi-med. "The resting- but stiU green 

 condition seemed to me to correspond 

 to Protococcus Felisii (K.), that which 

 turned red through desiccation, to Pr. 

 Orsinii." In pools near Freibm-g. Cohn 

 (Entwick. pp. 202, 203) detected two 

 vesicles in Chlmnydojnotias, below the 



point of insertion of the filaments, very 

 slowly but rhythmically contractile, and 

 mentions a species under the name of 

 Chlamydomonas hyalina, which he makes 

 S}Tionymous with Polytoma Uvella (E.), 

 and states to differ from Ch. Pulvisculus 

 only by the want of chlorophyll and of 

 a red speck (op. cit. pp. 140 *fe l69). He 

 moreover notes a new form, probably 

 generically distinct by having not a 

 globular but a winged prismatic figiu-e, 

 quadrangular on a transverse section, 

 with the two wings like two outstretched 

 points, although in other respects agree- 

 ing with Chlamydomonas Pulvisculus, 

 Perty (p. 85) objects to making Chla- 

 mydomomis a genus of Volvocina, and 

 refers it instead to the so-called "Spo- 

 rozoidia." He fm*ther tells us that Chi. 

 Pulvkc'ulus (E.) is rare about Bern, but 

 there is a smaller form very common, 

 which he proposes to call 



C. communis (Perty). — He finds also, 

 but less frequently, a more globular 

 variety, which appears to be the Tra- 

 chelomonas eniarginata (Eichwald), but 

 is in^ fact a Chlamydomonas, which he 

 names 



C. glohulosa (Perty). — His species 

 Hysginum pluviale ^and H. nivale (i. e. 

 Chlamydococcus) he suggests uniting, 

 with the species of Chlamydomonas, into 

 a group (of Sporozoidia) imder the name 

 of Schizonema. 



C. midtijilis (Fresenius"). — Round or 

 oval ; a distinct nucleus m the centre ; 

 granidar contents green ; filaments four, 

 longer than the cell ; at their base a rose- 

 colom-ed contractile vesicle, and poste- 

 riorly to this a red stigma. Lorica thin, 

 closely investing contents. As many as 

 six filaments seen in some larger speci- 

 mens. 1-92'" to 1-63'". In fresh water. 



C. hyalina (Cohn, Fresenius). — Elon- 

 gated elliptical ; roimded at both ends ; 

 filaments two, longer than the body; 

 posterior half of cavity occupied by gra- 

 nides ; a clear non-contractile space in 

 the centre ; a small contractile sac at the 

 base of the filaments. 1-66'" to 1-46'". 

 In ponds coloured by EuglencB. 



It is doubtftilly separable fi'om Chi. 

 Pulvisculus. 



Genus CHLAMYDOCOCCUS (Part I. p. 148) (XIX. 20-31).— Gonidia 



