BIGELOW: OCEANOGRAPHY OF MASSACHUSETTS BAY. 403 



Plankton notes. 



The following general notes on the plankton may be of value, 

 pending the appearance of the special reports on the more important 

 groups of pelagic organisms collected during the winter. 



The plankton which occupied the waters of Massachusetts Bay and 

 the coast region between Cape Ann and Cape Elizabeth in August, 

 1912, consisted chiefly of copepods {Loc. cit., p. 98), the most abundant 

 species at the offshore stations being Calanus finmarchicus, with 

 smaller numbers of Pseudocalanus elongatus, Centropages typicus, and 

 Metridia lucens; Anomalocera patersoni, so conspicuous by its brilliant 

 blue color, was often common on the surface, while the large boreal 

 copepod Euchacta norvcgica occurred sparingly, though more or less 

 regularly, in the hauls from intermediate depths. In addition to 

 these copepods, the amphipod Euthemisto compressa, the schizopod 

 Meganydiphanes norvcgica, the chaetognath Sagitta elegans, and the 

 coelenterates Staurophora mertensii, Aurelia, Cyanea, Plcuwbrachia pi- 

 leiis, Bolinopsis mfundibulum, and Beroe, were regularly represented 

 in the hauls. Other characteristic forms, less often taken, were the 

 pteropods Clione limacina and Limacina balea; Tomopteris helgo- 

 landica, and Sagitta serratodentata. Quantitatively the macroplankton 

 was very rich, the microplankton, on the other hand, was decidedly 

 scanty, consisting chiefly of the peridinian, Ceratium tripos, with 

 copepod eggs and nauplii, and very few diatoms. 



When we resumed work at the end of November, the macroplankton 

 was very much the same qualitatively as it had been in summer, Ca- 

 lanus finmarchicus being much the most numerous organism, with a few 

 other copepods, c. g., Metridia lucens, Centropages typicus, Siwd Pseudo- 

 calanus elongatus, and notably Euchacta norvcgica (10-0 fathoms.) 

 But Anomalocera, so numerous off Cape Ann in August, was noticeably 

 absent, nor did we meet it at any time during the winter or early 

 spring. Next in numerical importance were the chaetognaths, rep- 

 resented chiefly by Sagitta elegans, with a few S. serratodentata, the 

 relative quantity in the haul with the 4 ft. net being copepods, 75 cc, 

 Sagittae 15 ce. Considerable numbers of the amphipod Euthemisto 

 compressa, a few pteropods, Limacina balea, many Pleurobrachia 

 pileus, and fragments of Beroe, with a few crab and other de- 

 capod larvae were likewise found in the tow. The haul with the no. 

 20 silk net at the surface revealed a very scanty microplankton of 

 much the same type as in summer, chiefly Ceratium tripos, with an 



