346 THE PLANKTON OF THE FAROE CHANNEL AND SHETLANDS. 



I am greatly indebted to Miss Marion Lees for the beautiful 

 drawings which she has executed, and is still engaged upon, in 

 illustration of my plankton preparations. 



I. RADIOLARIA. 



The colony-building radiolaria are well represented round the 

 Shetland coasts and in the Faroe Channel. Haeckel, in the Challenger 

 Reijort, described and figured (Plate III.) a Collozoum, to which he 

 gave the name " G. cllipsoides, n. sp." Fowler {Proc. Zool. Soc., 

 December 13th, 1898, p. 1024) speaks of a Collozoum, which he 

 captured in 30 per cent, of epiplankton hauls in the Faroe Channel, 

 of apparently two species, neither of which could be attributed to 

 Collozoum inerme or to Haeckel's Collozoum ellipsoicles. 



COLLOZOUM. 



A Collozoum which I have captured in several tow-nettings, 

 and on many occasions round the coasts of Shetland, agreed in 

 all particulars with the same organism which I also obtained in 

 considerable quantity in surface tow-nettings in the Faroe Channel. 

 It bears considerable resemblance to Collozoum. jjelagicum (Brandt), but 

 does not fully agree in important particulars with any of the Collo- 

 zoums described by Brandt or Haeckel. 



The colonies are yellowish in colour, and sufficiently so when in 

 quantity to colour the whole capture a yellowish green. The jelly is 

 often delicate and easily torn. The colonies are for the most part 

 elongated, rarely spherical. Except in what are probably very young 

 colonies, the jelly is of moderately firm consistence. The individuals are 

 at once distinguished by the presence of one or more bright yellow oil 

 drops in the centre of the central capsule. The nests are not closely 

 packed, and the spaces between them are fairly regular. 



The zooids are for the most part spherical, and only in cases where 

 division is in progress or about to take place is this form departed 

 from. Then they are lengthened out in the axis, and are frequently 

 " fiddle-shaped." Division appears to be in progress in most of the 

 colonies captured by me in the autumn of 1900. 



The central capsules have a diameter, in the spherical condition, of 

 •09-'10 mm., and are packed with small round cells. In many colonies 

 the individuals contain only one oil drop, but most have two, and some 

 even three or four, occupying the exact centre of the capsule, and in 

 all cases of a deep yellow colour. Where zooids are undergoing division 

 these oil drops are often small and numerous. A fine membrane appears 

 to surround the central capsule, and round most nests there is a thick 



