338 University of California Publications in Zoology [Vol.22 



Cleve in three months, Daclyliosolen tenuis Cleve and Nitzschia seriata 

 Cleve in two months, and the following in one month : Chaetoceras 

 decipiens Cleve, Chaetoceras didymum Ehr., Leptocylindrus danicus 

 Schiitt, Bhizosolenia alata Btw., Skeletonema costatum Grev., and 

 Nitzschia pungens Grun. 



Certain forms which were originally recorded while counting have 

 been omitted from the tables for one or more months because of small 

 numbers or questionable identification. Their numbers have, however, 

 been included in the total diatoms. These include Amphiprora alata 

 Kiitz., Asterionella japonica CI., BaciUaria paradojra Gmel., Bacteri- 

 astrum. varians Laud., Biddulphia longicruris Grev., Cerataulina 

 bergonii Perag., Chaetoceras ralfsii CI., Climacosphenia moniligera 

 Ehr., Corethron criophilum Castr., Ditylium sp., Eucampia zoodiacus 

 Ehr., Grammatophora marina Lyngb., Hemiaulus heibergii CI., 

 Lauderia borealis Gran, Leptocylindrus danicus CI., Licmophora 

 lyngbyei Kiitz., Lithodesmium undulatum Ehr., Melosira sp., Nitzschia 

 closterium W. Sm., Nitzschia sp., Bhizosolenia faeroensis Ost., 

 Bhizosolenia hebetata Bail., Bhizosolenia obtusa Hensen, Bhizosolenia 

 robusta Norm., Bhizosolenia setigera Btw., Bhizosolenia styliformis 

 Btw., Stephanopyxis palmeriana Grun., Surirella sp., Thalassiosira 

 baltica Grun., Thalassiothrix longissima Cl.-Gr., and Thalassiothrix 

 nitzschiodes Grun. 



For similar reasons a number of species originally listed have been 

 grouped together in their genera or under a loosely applied species 

 name. This is especially true of some forms in Chaetoceras, Bid- 

 dulphia, Coscinodiscus, and Bhizosolenia genera. 



Gran's paper (190S) has been most helpful in identifications. 



SPECIES OF DIATOMS 



For economy of space I shall confine discussion mainly to the 

 eleven species represented in the lists of the five species most abundant 

 in one or more months. These are distributed unequally among six 

 genera listed in alphabetical order as follows: 



Chaetoceras. — This genus had relatively high numerical repre- 

 sentation in every month. It was responsible for the high records of 

 production in September, when several species far outnumbered 

 representatives of any other genus. No large Chaetoceras forms were 

 present and some were very small. Even so, the genus appears to be 

 more productive than other diatom genera in volume as well as in 



