THE PLANKTON OF THE FAROE CHANNEL AND SHETLANDS. 349 



I think it is possible that the Collozoum ellipsoides (n. S2).) described 

 briefly by Haeckel.* ("central capsules regularly ellipsoidal, very 

 large ; length 0"3-04, breadth 0'2 ; in every capsule 50-80 oil globules") 

 may be a stage of the same organism. This Collozoum has been 

 watched by me in the spore-forming stages, and I have studied both the 

 anisospore and isospore conditions. A study of these Collozoums has 

 convinced me how little reliable can be a differential classification of 

 these organisms based on the shape of the zooids, as indicated by 

 Haeckel (p. 24 of the same monograph). 



These swarms of Collozoum were observed in Scapa Flow to come to 

 the surface on an exceedingly hot day with a burning sun and quite 

 calm sea. As soon as any ripple of the surface occurred, with a breeze 

 of wind, they disappeared below the surface, and were found 10-12 

 fathoms deep. It is probable that temperature affects them but little, 

 as I experimentally submitted the living colonies to a temperature of 

 33° F. and found that after two hours' treatment they still floated at 

 the surface, and at the other extreme a temperature of 80 °F. did not 

 affect their vitality. Chcenicosphcera murrayana has been captured by 

 me, living, in the sea at a temperature of 29° F. Wind, tidal and other 

 currents have probably more to do with distribution in these cases than 

 temperature. 



In assigning any Collozoum to its specific place, no system can be 

 reliable which does not take into full account the various stages in the 

 life-history of the organism. I therefore quote from Brandt's mono- 

 graph the following data arranged in tabular form and with which I 

 have incorporated the new species (to which I have given the name 

 C. hrandtii). These serve for the discrimination of the known European 

 species, or as type forms round which others may be grouped. 



* Challenger Report, " Radiolaria," \). 26. 



