1917] Gardner: New Pacific Coast Marine Algae I 383 



method outlined I)}' Reinliardt in zoospore formation. She states, 

 however, that the cells at times divide into several large sections prior 

 to spore formation, but is unable to interpret the function of such 

 division. It may possibly be that these are the earlier successive 

 divisions which usually result in spore or gamete formation, but 

 which for some reason have been arrested in development. Moore's 

 plant follows the same method as that of C. Porphyrae in the matter 

 of the formation of reproductive bodies. Wille and Moore report 

 "zoospores" with four cilia. Concerning this point my observations 

 are incomplete with reference to C. Porphyrae. The reproductive 

 bodies formed in this species, so far as I have observed, are gametes. 

 They have two cilia. I have observed them in great abundance, and 

 have observed their conjugation. The gametes escape singly through 

 the surface aperture, instead of the entire mass intact within a utricle 

 as reported for certain species, e.g. that found by Moore. 



There is but a single large pyrenoid in C. Porphyrae, agreeing in 

 this respect with C. Mooreii and C. ReinhardUi. Wille characterizes 

 the genus Chlorochytrium as having many pyrenoids, but West looks 

 upon that character more as specific than as generic. 



West (1916, p. 212) is of the opinion that the shape of a chromato- 

 phore can not ordinarily be considered of sufficient stability to be 

 used as a primary basis of generic distinction. I am inclined to agree 

 with him on this point. Both Moore and I have shown that in the 

 forms upon which we have worked the shape of the chromatophore 

 is extremely variable, at times possessing radiating, flattened lobes, 

 only partl}^ covering the cell wall, but usually at maturity covering 

 the entire wall. 



The four genera which West has merged into Chlorochytrium 

 Cohn ('72) are Endosphaera Klebs ('81), Scotinosphaera Klebs 

 ('81), Chlorocystis Reinhardt ('85), and Stonmtochytrium Cun- 

 ningham ('88). They all agree in being l!olo])hytic, unicellular, 

 spherical or nearly so, wholly or partially endophytic plants with 

 a single chromatophore, covering the wall more or less completely 

 and containing one or more pyrenoids. Reproduction is by gametes 

 or by zoosphores or by both. The plant which I have discovered and 

 described above, growing in Porphyra, possesses these characters and 

 I have consequentl}^ allied it with the genus Chlorochytrium in the 

 larger sense of West. 



Chlorochytrium Porphyrae differs principally from Chlorochy- 

 trium Mooreii in having only bieiliate gametes, as far as known, in- 



