ULTRASTRUCTURE OF PYRAMIMONAS-CYRTOPTERA SP-NOV (PRASINOPHYCEAE), A SPECIES WITH 16 FLAGELLA FROM NORTHERN FOXE BASIN, ARCTIC CANADA, INCLUDING OBSERVATIONS ON GROWTH-RATES

A new species of the genus Pyramimonas is reported from the Canadian Arctic, the first record of Pyramimonas from northern Foxe Basin, Northwest Territories. The general structure of the cell and six types of scales are described. Pyramimonas cyrtoptera sp.nov. is remarkable in possessing 16 flagella, two chloroplasts, two pyrenoids, and two pairs of eyespots of unequal size. It is the largest known species of Pyramimonas, measuring 38-42-mu-m in length. The presence of 16 flagella and two chloroplasts sets it apart from all other species of Pyramimonas. Pyramimonas cyrtoptera belongs to the subgenus Pyramimonas. A new type of hair scale is reported for members of this group. The growth responses of P. cyrtoptera to variations in temperature and salinity indicate that it is as cold stenothermal and euryhaline.