1920] 8etchell-Gard)ier: Chlorophyceae 155 



rliizoidal portion. It is now placed near to I'roiosiphon, wiiieli it 

 more closely resembles than any other genus. The description given 

 above is adapted from Collins {loc. cit.) and expresses well the general 

 characters. 



Halicystis ovalis (Lyngb.) Aresch. 

 Plate 14, fig. 3 



Thalhis solitary or gregarious, obovate-ovoid, 0.5-1 cm. high, 

 about half as wide; membrane tough, 10-12/* thick; basal prolongation 

 penetrating the substratum; zoospores 12-14/x long, 7-8/x wide; 

 gametes ( ?) 7-8/x long, 2-3/i wide. 



Growing on Lithothamnion and on other crustaceous corallines 

 adhering by means of the rhizoidal portion penetrating deeply into 

 the host. Vancouver, British Columbia, to Monterey, Califoi'nia. 



Areschoug, Phyc. Scand., part II, 1850, p. 447 ; Kuckuck, Abhandl. 

 Meeresalg., 1907, p. 189, pi. Ill; Collins, Green Alg. N. A., 1909, 

 p. 372. Vulonid oralis (Lyngb.) Agardh, Sp., vol. 1, part 2, 1822, 

 ]). 4:]1; Saunders, Four Siphon. Alg., 1899, ]). 2, i)l. 350, f. 2 a, b; 

 Setchell and Gardner, Alg. N. W. Amer., 1903, p. 232. Gastridium 

 ovale Lyngbye, Hydr. Dan., 1819, p. 72, pi. 18 B. 



This very curious and interesting species has been most carefully 

 studied, deserilx'd and illustrated by Kuckuck (1907) and seems to 

 be the same as tluit found on our own coast. Very little material is 

 available for study, neither of the present writers has had the oppor- 

 tunity of collecting it, and only one of tlunn (Setchell) has had the 

 privilege even of examining a living plant. In general aj)pearance 

 and structure, however, the Pacific Coast plant agrees thorougldy with 

 tlie descriptions of the European writers. 



It was first credited to our coast by Saunders (1899) who found 

 it at "Point Lobos" (or Point Carmel) in Monterey County, Califor- 

 nia. Later it was found in successive years at a locality near Point 

 Cj'press, only a few miles north of "Point Ijobos" by Professor Harold 

 Heath of Stanford ruiversity, and Ihc third and last locality is Port 

 Renfrew in British Columbia, where it was collected by Misses J^uller 

 and l'()ih'\-. It is always found growing on living crustaceous coral- 

 lines into tlie tluillus of which it bores its way. It will probal)ly be 

 found at othci" points along the coast, since it undoubtedly escapes 

 observation as it is small and grows at. or just below, the lowest 

 tide mark. 



