1918] Gardner: New Pacific Coast Marine Algae HI 459 



found in several species that the gonidia result from successive divi- 

 sions in different planes. This condition is notably true of D. protca 

 of this paper. A further exception to the statement of Kirehner 

 must be made in Z>. Leibleiniae (Reinsch) Born, and Thur. and D. 

 suffulta Setehell and Gardner (in Gardner, 1918, p. 440), in that only 

 a portion of the protoplast of the gonidangium is converted into 

 gonidia, the basal portion in each species uniformly remaining sterile. 

 There is but little likelihood of confusing Dermocarpa with either 

 Chamaesiphon or Godlewskia, on account of their cylindrical shape 

 and method of formation and liberation of gonidia, or even with 

 ClasticUum, wliieh is narrow and cylindrical and possesses a setum 

 at the outer end ; but in attempting to place a species like D. sphae- 

 7-icia, or D. Sphaeroidea Setehell and Gardner {in Gardner, 1918, 

 p. 440) the question arises as to which genus, Dermocarpa or Cyano- 

 cystis, if both of these are to be considered valid genera, should receive 

 them. The method of escape of gonidia in D. sphaeroidea has not 

 been determined, but in D. sphaerica the whole wall of the gonidan- 

 gium dissolves and the group of gonidia are left free in position (pi. 39, 

 fig. 14). The only distinction between Cyanocystis and Dermocarpa, 

 as brought out by both Kirehner and Forti, is that of the method of 

 escape of gonidia. In the former they escape by a circumscissile 

 rupture and in the latter by a dissolution of the apex of the goni- 

 dangium. If the method of escape of the gonidia is to be taken as 

 sufficient for generic distinction, it will be necessary to create another 

 genus for D. sphaerica which does not conform to either of the above 

 methods. It seems preferable in this case to refrain from extending 

 the number of genera but rather to reduce it, and since Dermocarpa is 

 the older genus, adopt that to receive our species and reduce Cyano- 

 cystis, in ease further study makes it necessary or desirable. 



Xenococcus acervatus Setehell et Gardner sp. nov. 

 Plate 39, fig. 1.3 



Cellulis omnino epiphytieis, in directionibus duobus ad hospitem 

 perpendicularibus divisis, colonias primo unistratosas demum acer- 

 vatas confusas et indefinitas formantibus; cellulis primo angulatis, 

 mox sphaericis aut pyriformibus, '^-Q>ix diam., parietibus tonuil)us, 

 hyalinis; cytiophismate homogeneo, dilute coeruleo-viridi ; gouidangiis 

 ad hue ignotis. 



Cells wholly epiphytic, dividing in two pianos perpendicular to the 

 host, building colonies at tirst one cell deep, later confusedly heaped 

 up, of indefinite extent ; cells angular at first, soon becoming si)herical 



