[bailey-mackay] diatoms FROM VANCOUVER ISLAND, B. C. 147 



found near Vancouver Island, apparently of the species Ehrenbergii 

 Bail., but A. ornatus A.S., which occurs at least in a varietal form at 

 San Francisco, may also be represented among them. 



ASTEROMPHALUS. . 



The only species of this genus observed is believed to be Asr 

 arachne Bréb. It is distinguished by the presence on its circular disc 

 of an excentric generally five-rayed figure dividing it into five unequal 

 sectors, the longer ray being slender with the shorter stout rays bila- 

 terally disposed to it, forming a somewhat spider-like outline. 



ASTEROLAMPRA. 



This genus closely resembles the last, but the sectors are similar 

 and equal, while the rays are all alike from the centre to the circum- 

 ference of the disc. Only one specimen was observed, but the species 

 could not be satisfactorily identified. 



AULACODISCUS. 



This beautiful genus represented by Au. Oregonus Bailey was 

 found in only one of several gatherings, from Newcastle Island near 

 Nanaimo, but it is here tolerably abundant. Dr. MacKay does not 

 think it agrees exactly with the specific description, and has therefore 

 provisionally marked it as var. octavius in allusion to its eight sectors. 



AULISCUS. 



This genus occurs with the last, to which it is closely related. 

 There would appear to be several species of which one is Au. coelatus 

 Bail. var. riphis A.S., and another Au. sculptus Sm. 



HYALODISCUS. 



Representatives of this genus are very common in the collec- 

 tions under review, and apparently represent four species. Of them 

 H. laevis Ehr. is at once the most abundant and of largest size. H. 

 suhtilis Ehr. is usually much smaller but vaiiable. H. Whitneyi 

 Ehr. and H. stelliger Bail, are, perhaps, of doubtful occurrence. 



ACTINOPTYCHUS. 



A. undulatus Ehr. is a very widely distributed Diatom, is not 

 rare in the Vancouver Island collections, and is easily recognized. 

 In addition two other forms which may be new were observed. One 



