1919] Seichell-Gardner : Myxophyceae 33 



being in excellent vegetative and reproductive conditions is clearly 

 definable. The gonidia appear to be the results of two lines of devel- 

 opment of the vegetative cells. Some gonidia seem not to divide 

 vegetatively after coming to rest, but continue to increase in size until 

 maturitj'- is reached, then by a few successive internal divisions the 

 whole protoplast is progressively converted into gonidia. In some 

 cases the first division takes place horizontally cutting off a small por- 

 tion of the base of the protoplast, which in some instances seems to 

 remain sterile, at least the whole upper part is converted into gonidia 

 before the basal portion is (pi. 5, fig. 11a). In other cases the first 

 division is through the center of the cell. Other gonidia develop for 

 a time after coming to rest, then divide vegetatively several times, 

 generating small colonies before advancing to the gonidial stage 

 (pi. 5, fig. 116). 



3. Xenococcus Cladophorae (Tildcn) S. and G. 



Plate 4, fig. 8 



Plants forming a more or less continuous layer one cell deep, or 

 occasional!}^ associated in small groups ; cells variously shaped, angu- 

 lar, prismatic, spheroidal or pyriform, 8-15/x, occasionally 22ju, diam. ; 

 cell walls prominent, hyaline, homogeneous, often diffluent ; protoplast 

 pale blue-green, homogeneous ; gonidangia the same shape and size as 

 the vegetative cells; gonidia formed by successive divisions of the 

 protoplast, 1.5-2/A diam. 



Growing on Cladophora sp. in a tide pool, Baird Point, Strait of 

 Juan de Fuca, British Columbia. 



Setchell and Gardner, in Gardner, New Pac. Coast Alg. Ill, 1918a, 

 p. 461, pi. 38, fig. 8. Pringsheimia scutata f. Cl-adophorae Tilden, 

 Amer. Alg. (Exsicc), no. 382, type. Chlorogloea tuberculosa Setchell 

 and Gardner, Alg. N.W. Amer., 1903, p. 182 (in part) ; Tilden, Minn. 

 Alg., vol. 1, 1910, p. 46 (in part). 



So far as we are able to discover on the available specimens of 

 Cladophora distributed by Miss Josephine Tilden under no. 382 of her 

 American Algae, there are no epiphj^tes present belonging to the 

 Chlorophyceae. On the contrary, there is a mixture of species belong- 

 ing to the Myxophyceae. 



One of these, a very small-celled form, very sparse in the dis- 

 tribution at our disposal, as suggested by us (1903, p. 182), seems 

 to be closely related to Chlorogloea tuberculosa (Hansg.) Wille. The 



