PALMELLACE^E. 



[ 488 ] 



PALMELLACE^. 



into two or four, and by ciliated zoospores. 

 Many exhibit three forms, — 1. active; 2. 

 quietly vegetating by subdivision ; 3. resting 

 form, with a tough membrane. 



Synopsis of British and some allied Conti- 

 nental Genera. 



I. Chlorococcum, Ag. Frond pulveru- 

 lent, scarcely existing, consisting of a dryish 

 stratum; cells with a simple coat, loosely 

 coherent, with little amorphous gelatinous 

 matter, 



II. Protococcus, Ag. Frond a slimy 

 stratum composed of cells irregularly cohe- 

 rent, with little mucus. Dissolving in water 

 into free cells, dividing into two and four 

 ciliated zoospores. 



III. Palmella, Lyngb. Frond a tough 

 amorphous jelly ; cells with a simple indi- 

 stinct coat, imbedded in abundant gelatinous 

 matter, containing numerous very minute 

 granules. 



IV. Urococcus, Hass. Frond gelatinous, 

 cells with a single coat imbedded in the ends 

 of striated mucous tubes, which constitute 

 the gelatinous mass of the frond. 



V. Glceocapsa, Kiitz. Frond very mi- 

 nute, gelatinous, composed of cells enclosed 

 in wide gelatinous coats, these again en- 

 closed in fours in a gelatinous mother-cell, 

 the latter again encased in like manner, and 

 so on, the older coats gradually becoming 

 indistinct and mucous. 



VI. Merismop^dia, Meyen. Frond 

 very minute, flat, squarish, floating, com- 

 posed of cells coherent in fours and sixteens 

 into a gelatinous plate (see Sarcina). 



VII. CoccocHLORis, Sprengel. Frond 

 gelatinous, globose, composed of minute 

 cells imbedded, scattered, or agglomerated 

 in a continuous gelatinous substance. 



VIII. HoRMOSPORA, Breb. Frond a ge- 

 latinous, simple or branched tube, broad, 

 soft and transparent, containing a single 

 row of cells approximated in twos or fours. 



IX. Hydrurus, Ag. Frond filiform, 

 attached, slippery, simple or branched, com- 

 posed of tough gelatinous material, contain- 

 ing longitudinal rows of cells. 



X. Tetraspora, Link. Frond more or 

 less definite, foliaceous, gelatinous, contain- 

 ing imbedded cells, arranged in distant groups 

 of four, or occasionally of two. 



XI. Botrydina, Breb. Frond very mi- 

 nute, subglobose, consisting of a vesicle with 

 the wall composed of a single layer of pa- 

 renchymatous cells, containing free cells in 

 the interior, finally discharged. 



XII. ScHizocHLAMYs, A.Br. Stratum 

 gelatinous, composed of aggregated distinct 

 cells, the contents of which divide into two 

 or four portions, and escape by the regular 

 fission of the cell-membrane into tw'O or fom* 

 segmental fragments. 



XIII. Apiocystis, Nag. Frond very 

 minute, bladder-shaped, attached, enclosing 

 cells (gonidia) arranged in foiu"S upon the 

 wall, subsequently breaking out and swarm- 

 ing. 



XIV. Palmodictyon, Ktz. Frond ge- 

 latinous, filiform, branched; branches reti- 

 cularly divided and anastomosing, composed 

 of large vesicular cells containing minute 

 coloured cells, the minute cells escaping as 

 zoospores. 



Doubtful organism. 



Sarcina, Goodsir. Fronds (?) flat, ex- 

 tremely minute, squarish, tough, formed of 

 coherent squarish cells, combined in quater- 

 nate groups to the number of eight, sixteen 

 or sixty-four. Found floating free in the 

 liquid of the human stomach, &c. 



Excluded genera {doubtful), 



Hcematococcus, Ag. = Protococcus. 



Polycoccus, Kiitz. = Protococcus. 



Exococcus, Nageli = ? 



Sorospora, Hass. = Glonocapsa or Proto- 

 coccus. 



Characium, Al. Braun = apparently the 

 germinating gonidium of an (Edogonium, 

 producing zoospores. 



Microcystis, Kg. Probably a resting form 

 of Euglena. 



Anacystis, Kg. Do. 



Ccelocystis, Kg. Do. 



Polycystis, Kg. Do. 



Botryococcus, Kg. Do. 



Botryocystis, Kg. = Form of Volvox ? 



Cylindrocystis, Breb. =zPalmogloea, Kiitz. 



Microhaloa, Kg. = Protococcus and Pal- 

 mella. 



Trichodictyon, Kg. = ? 



Trichocystis, Kg. = Actinophrysl 



Polmophyllum, Kg. = Prasiola ? 



Gomphosphceria. Kg.=:young ColeochcBte'? 



Palmodictylon, Nag. = germinating spores 

 of a moss? 



Chroococcus, Nag. ^ Protococcus. 



Aphanocapsa, Nag. = Palmella. 



Ccelosphcerium, Nag. = Coccochloris. 



Synechococcus, Nag. = Protococcus. 



Glosothece, Nag. = Palmoglcea ? 



Aphanothece, Niig. =: Palmella ? 



Pleurococcus, Menegh. = Protococcus. 



