PLANKTON OF THE GULF OF MAINE 



429 



C. May 5, 1915, station 10267 (fig. 121): 

 Diatoms very abundant. 

 ♦Chffitoceras densum fully 50 per cent 

 of the catch. 



May 5, 1915 — Continued. 



Chsetoceras criophilum. 

 *Ch. decipiens. 

 *Rhizosolenia semispina. 

 ♦Thalassiothrix longissima. 



8. Nokth Channel 



A. March 20, 1920, station 20078: 5S 

 Very few diatoms. 

 Chxtoceras contortum. 

 Ch. criophilum dominant. 

 Ch. didymum. 

 Coscinodiscus subbulliens. 



Rhizosolenia semispina S. 

 B. April 15, 1920, station 20105: 

 Diatoms abundant. 

 ♦Chxtoceras decipiens dominant. 

 *Ch. diadema dominant. 

 ♦Thalassiothrix nitschioides also abun- 

 dant. 



Bacteriosira fragilis S. 

 *Biddulphia aurita. 



April 15, 1920— Continued. 



Chxtoceras contortum S. 

 *Ch. criophilum. 

 *Ch. debile. 

 *Ch. laciniosum. 

 *Ch. teres S. 



*Coscinodiscus asteromphalus. 

 *C. denarius S. 

 *Nitschia seriata. 

 *Pleurosigma stuxbergii S. 

 ♦Rhizosolenia alata. 

 *R. semispina. 



R. styliformis. 

 *Thalassiosira decipiens. 

 *Th. gravida. 

 *Th. hyalina. 



Th. nordenskioldi. 



9. — Brown's Bank 



A. March 13, 1920, station 20072. 58 



Scanty diatom and Ceratium plankton. 

 Coscinodiscus asteromphalus dominant. 

 Coscinodiscus sp. dominant. 



Chxtoceras diadema. 

 Ch. debile. 

 Ch. mitra. 

 Thalassiothrix nitschioides. 



B. April 16, 1920, station 20106: 



Diatoms moderately abundant. 

 ♦Chxtoceras contortum dominant. 

 *Ch. debile dominant. 

 *Ch. decipiens dominant. 



April 16, 1920— Continued. 



♦Ch. diadema dominant. 

 ♦Thalassiosira gravida abundant. 



♦Chxtoceras atlanticum. 



Ch. criophilum. 

 *Ch. laciniosum. 

 ♦Coscinodiscus asteromphalus. 



Coscinosira polychorda. 

 ♦Rhizosolenia semispina. 

 ♦R. setigera. 

 ♦Thalassiosira decipiens. 



Th. hyalina. 

 ♦Th. nordenskioldi. 



Thalassiothrix nitschioides. 



A. April 16, 1920, station 20107: 

 Diatoms very abundant. 

 ♦Chxtoceras contortum dominant 

 ♦Ch. debile dominant. 

 *Ch. decipiens dominant. 

 ♦Thalassiosira gravida dominant. 

 ♦Th. nordenskioldi. 



♦Biddulphia aurita. 

 ♦Chxtoceras atlanticum. 

 ♦Ch. criophilum. 

 Ch. diadema. 

 " Not examined by Doctor Mann. 



10. — Eastern Channel 



. April 16, 1920— Continued. 



♦Ch. laciniosum (with endocysts). 



♦Coscinodiscus oculus-iridis. 



♦Fragilaria oceanica. 



♦Navicula frigida S. 



*N. vanhoffeni S. 



♦Rhizosolenia alata. 



♦R. semispina. 



♦Thalassiosira bioculata. 



*Th. hyalina. 



♦Th. sp. ? 



♦Thalassiothrix nitschioides. 



