114 BULLETIN OF THE BUREAU OF FISHERIES 
and 16), filling the waters of the bay and the eastern part of Vmeyard Sound. ‘The 
seasonal distribution of diatoms in Long Island Sound in 1922-23, during the 
winter months, was found to be very similar to that of Woods Hole except that the 
swarms appeared slightly later. 
d¢ 48 3 8 
Aetinoptyehns undulatus cae OFaeeeaeoewenaecatversereee : 
Febo 
Jule 
Auge 
Sepo 
Octe 
Nove, 
DeGs 
Asterionella japonica 
Bacteriastrum delicatulum H Be eeseeeeceeet 
Biddulphia alterans t cf H i oH He 
Biddulphia favus H EEE EEE 
Biddulphia granulata Het : 
Biddulphia biddulphiana HE 
Biddulphia vesicvlosa H Ee 
Corethron valdiviae : HH 
Dityliwm brightwelli 
¥ragilaria crotonensis 
Grammat ophora marina 
Grammatophora serpentina 
Guinardia flaccida 
Hyalodiscus stelliger i rth 
Leptocylindrus danicus Ht 
Liomophora flavellata PSSASEEER PEPE : BEECH oEtoet ete 
Licmophora lyngbyei GSESSHESHECREEHSEE : 
Melosira borreri : Eo 
Nitzschia closteriun + 
Nitzsohia longissima H 
Nitzschia paradoxa Sete ts 
Nitzschia seriata ose aissetts E : \ 
Paralia sulcata cof sie Sa 
Rhabdonema adriaticun : 
Skeletonema costatun strate 
Striatelle mipunctata = 
Synedra gallionii 
Synedra undulata 
Thalassiosira decipiens 
Thalassiosira hyalina 
Thalassiosire nordenskiolaiijsie 
Thalassiothrix frauenfeldii eaubedady PeEeeee 
Thalassiothrix longissima ; EEEEEREEEE i 
Thalassiothriz nitzschioidest= 
Distephams speculun — 
Dictyocha fibula { H 
Cerataulina bergonil + 
Cyolophora tenuis Ht 
aL 
: 
Fra. 18.—Distribution of diatoms and Silicoflagellata in 1923 (excluding Chsetoceros and Rhizosolenia) 
The pelagic diatoms of the Woods Hole region may be grouped under three 
headings—tychopelagic, oceanic, and neritic. The tychopelagic group is made up 
of semi-bottom forms, which often occur in coastal waters in enormous numbers. 
They are carried about by the winds and tides, usually without relation to any 
