130 Marine Microbiology 



TABLE 2 

 Average Division Rate of Plankton Algae of the Black Sea in Cultures 



Species Months 



VI VII VIII IX 



Diatomeae 

 Skeletonema costatum 



(Grev) CI. 28 



Chaetoceros sociolis Laud. — 

 Chaetoceros curvisetus CI. 41 

 Leptocylindrus danicus CI. 39 

 Cerataulina bergonii Perag. 89 38 

 Thalassionema nitzschioides 



Grun. 65 



Coscinodiscus granii 



Goulgh. 94 



Rhizosolenia alata Bright 65 

 Rhizosolenia calcar 



avis Schultze. 42 



Ditylum brightwellii 



(West) Grun. 37 



Dinoflagellatae 

 Exuviaella cordata Ostenf. 58 

 Prorocentrum micans Ehr. 80 

 Peridinium triquetrum 



(Ehr) Lebour. • — 



Peridinium steinii Jorg. — 



Peridinium trochoideum 



(Stein) Lemm 62 



Gymnodinium wulfii 



Schiller 48 



Glenodinium lenticula 



(Berdh) Schiller — 



Volvocineae 

 Chlamydomonas minima 



Schiller 

 Carteria willei 



Schiller 



46 35 28 23 



87 



60 70 79 — 



35 31 27 25 38 



35 25 28 40 44 



38 33 34 38 46 47 



— 42 44 48 



48 42 — — 



24 16 18 26 30 32 44 



18 12 16 21 24 26 30 48 



the same species in the sea. The period of a high division rate 

 for many species in cultures lasts always somewhat longer than 

 the period of mass development in the sea. 



However, in some years their maxima do not always coincide 

 in time. This is apparently due to some biotic relationships be- 

 tween the different species of planktonic algae. The observations 



