PLANKTON OF THE GULF OF MAINE 



425 



B. April 9, 1920, station 20093." 

 Diatoms very abundant. 

 *ChaHoceras decipiens dominant. 

 *Thalassiosira nordcnskioldi dominant. 

 *Cha?toceras debile abundant. 

 *Rhizosolenia semispina abundant. 



♦Biddulphia aurita. 



♦Chastoceras atlanticum. 



*Ch. contortum. 



*Ch. criophilum. 



*Ch. diadema. 



*Ch. furcellatum. 



*Ch. scolopendra. 



*Ch. sociale. 



*Ch. teres. 



*Ch. willei. 



♦Coscinodiscus asteromphalus. 



*C. eoncinnus. 



*Pleurosigma stuxbergii. 



♦Rhizosolenia setigera. 



*Thalassiosira gravida. 



♦Thalassiothrix nitschioides. 



Nearer the coast, in Ipswich Bay, April 9, 

 1920, station 20092: 

 ♦ChaHoceras contortum dominant. 

 *Ch. debile dominant. 

 *Thalassiosira gravida dominant. 



*Biddulphia aurita. 

 ♦ChaHoeeras atlanticum S. 



Ch. contortum. 

 *Ch. decipiens. 

 *Ch. diadema. 

 *Ch. furcellatum. 

 *Ch. laciniosum. 

 *Ch. teres. 

 *Ch. wighami. 

 *Coscinodiscus eoncinnus. 

 ♦Rhizosolenia semispina. 

 *R. setigera. 



Thalassiosira nordenskioldi. 

 *Thalassiothrix nitschioides. 



3. — Off Cape Elizabeth 



A. March 4, 1920, station 20059 « (fig. 119): 

 Diatoms abundant. 

 *Thalassiosira nordenskioldi dominant. 

 *Cha?toceras contortum abundant. 



Biddulphia aurita. 



Chxtoceras debile. 

 *Ch. decipiens. 

 *Ch. diadema. 



Ch. didymum. 



Ch. sociale. 



Ch. teres. 



Ch. sp. ? 

 *Coscinodiscus curvulatus. 

 *C. excentricus. 

 *Ditylium brightwellii. S. 



Lauderia glacialis 

 *Pleurosigma stuxbergii S. 

 *Rhizosolenia setigera. 

 *R. semispina. 



Skeletonema costatum. 



Thalassiothrix nitschioides. 

 *Thalassiosira gravida. 

 B. April 10, 1920, station 20095: 



Diatoms very abundant. 

 ♦Chsetoceras debile dominant. 



B. April 10, 1920— Continued. 



*Ch. contortum dominant. 

 ♦Thalassiosira nordenskioldi dominant. 



Biddulphia aurita. 

 *Cerataulina bergonii S. 

 ♦Chretoceras atlanticum. 

 *Ch. decipiens. 

 *Ch. diadema. 



Ch. didymum. 

 *Ch. laciniosum. 

 *Ch. scolopendra S. 

 *Ch. sociale. 

 *Ch. teres. 

 *Ch. willei. 

 *Coscinodiscus asteromphalus. 



Coscinosira polychorda. 

 ♦Eunotia areus S (accidentally present). 

 *Nitschia closterium. 

 *N. seriata. 



*Rhizosolenia semispina. 

 *R. setigera. 

 *Skeletonema costatum. 

 ♦Thalassiosira gravida. 

 ♦Thalassiothrix nitschioides. 



« The list for Platts Bank the neit day (station 20091) was the same, except that it included 'Chxtoceras densum and Ch. 

 didymum, 'Coscinadiscus curvulatus, *Nitschia seriata, and Skeletoaema costatum, but lacked Chxtoceras furcellatum, Ch. willei, aud 

 Thalassiothrix nitschioides. 



» The list was the same near Seguin Island on that day (station 20058, fig. 117), except that it lacked Chxtoceras diadema, Coscino 

 discus excentricus, and Rhizosolenia semispina, but included * Chxtoceras atlanticum, ' Ch. criophilum, • Ch. laciniosum, ' Ch. willei, 

 * Coscinodiscus asteromphalus, *C. eoncinnus, and C. subtilis. 



