PLANKTON OF THE GULF OF MAINE 



427 



F. September 15, 1915 — Continued. 



*Coscinodiscus concinnus dominant. 



Chaetoceras constrictum. 



Ch. decipiens. 

 *Ch. diadema. 



♦Coscinodiscus oeulus-iridis. 

 *C. asteromphalus. 

 ♦Ditylium brightwellii. 

 ♦Melosira erenulata. 

 *Nitschia closterium. 

 *Paralia sulcata. 

 *Pleurosigma normanii. 

 *Rhizosolenia setigera. 

 *R. shrubsolei. 

 *Skeletonema costatum. 

 ♦Thalassiosira nordenskioldi. 

 ♦Thalassiothrix longissima. 

 O. October 9, 1915, station 10328: 



Diatoms moderately abundant. 

 ♦Choetoceras decipiens numerous. 

 *Rhizosolenia setigera numerous. 



Q. October 9, 1915— Continued. 



♦Thalassiosira decipiens numerous. 

 ♦Thalassiothrix longissima numerous. 



♦Actinoptychus undulatus. 

 *Cha3toceras breve. 

 *Ch. didymum. 

 *Ch. constrictum. 



Ch. danicum. 



Ch. debile. 

 *Ch. difficile (with endocysts). 

 *Ch. laciniosum. 

 *Coscinodiscus concinnus. 

 *C. excentricus. 

 ♦C. asteromphalus. 

 *C. oeulus-iridis. 



Coseinosira polychorda. 

 ♦Ditylium brightwellii. 

 *Paralia sulcata. 

 *Rhabdonema arcuatum. 

 *Rhizosolenia shrubsolei. 

 *Thalassiosira hvalina. 



5. — Bay of Fdndy 



A. Petit Passage, Nova Scotia, June 10, 1915: 

 Diatoms very abundant. 

 ♦Choetoceras contortum dominant. 

 *Ch. decipiens dominant. 

 *Ch. scolopendra dominant. 

 ♦Rhizosolenia semispina dominant. 



♦Actinoptychus undulatus S. 



Choetoceras constrictum. 

 *Ch. criophilum. 

 *Ch. debile. 

 *Ch. diadema. 



6. — Banks 



A. Nova Scotia, etc. — Continued. 

 *Ch. laciniosum. 

 *Ch. teres (with endocysts). 

 ♦Corethron valdivise. 

 ♦Coscinodiscus concinnus. 

 *Nitschia seriata. 

 ♦Paralia sulcata S. 

 ♦Rhabdonema arcuatum S. 

 ♦Rhizosolenia alata. 

 ♦Thalassiosira gravida. 

 *Thalassiosira nordenskioldi. 



off Western Nova Scotia 



A. Near Seal Island, Nova Scotia, March 23, 

 1920, station 200S4: 

 Diatoms scarce. 

 ♦Actinoptychus undulatus dominant. 

 ♦Biddulphia aurita dominant. 

 ♦Coscinodiscus concinnus dominant. 

 ♦C. asteromphalus dominant. 



Choetoceras decipiens. 

 ♦Paralia sulcata. 

 ♦Pleurosigma stuxbergii. 

 ♦Rhabdonema arcuatum. 

 ♦Rhaphoneis surirella. 

 ♦Rhizosolenia setigera. 

 ♦R. semispina. 



Skeletonema costatum. 

 ♦Thalassiosira gravida. 

 ♦Thalassiothrix nitschioides. 



B. South of Seal Island, Nova Scotia, April 15, 

 1920, station 20104: 



Very abundant diatom plankton. 

 ♦Choetoceras contortum dominant. 

 ♦Ch. debile dominant. 

 *Ch. diadema dominant. 



♦Actinoptychus undulatus S. 

 ♦Biddulphia aurita. 

 ♦Choetoceras criophilum. 

 ♦Ch. decipiens. 



♦Ch. laciniosum (with endocysts). 

 ♦Ch. seiracanthum. 

 ♦Paralia sulcata. 

 ♦Rhizosolenia semispina. 

 ♦Thalassiosira gravida. 



Th. nordenskioldi. 

 ♦Th. decipiens. 

 ♦Thalassiothrix nitschioideB. 



