274 RECORDS OF THE AUSTRALIAN MUSEUM 



not seem to abound near the coast, and, as far as Port Jackson 

 and Broken Bay are concerned (and I liave little doubt the same 

 holds good of the other inlets), a simple Radiolarian of any kind 

 is a 7'ara avis in the surface net, and the colonial forms, so far as 

 my experience goes, never occur. 



None of the three species mentioned above occur in the present 

 collection. On the other hand it comprises about seven species 

 previously known from other parts of the ocean. 



GentlS COLLOZOUM. 



The absence of skeletal parts in the genus CoUozoum^ renders 

 the identification of the species in that genus a matter of con- 

 siderable difficulty — particularly when one has to deal with pre- 

 served material, in which the form of the colony may not be 

 recognisable. This difficulty is increased by certain discrepancies 

 between the determinations of Haeckel on the one hand and 

 of Brandt on the other. Thus with regard to the characters of 

 the original species, G. inei-mf, supposed by the former to be cos- 

 mopolitan, and to be subject to considerable variation, there is a 

 wide divergence in the statements of the two authors. According 

 to Haeckel's description in the " Monographic, "' in this species 

 the zooids are usually spherical, but may be compressed 

 spheroids, or lens-shaped, or, rarely, elliptical, and tliere is a 

 thick, often double, capsular membrane ; in the " Report "" the 

 specific name is restricted to forms with spheiical zooids and a 

 thin, simple-edged membrane. According to Brandt^ on the 

 other hand, in the species in question the zooids are discoid or 

 irregular, and a membrane is entirely absent. 



Of the specimens oi Collozoum obtained during tlie "Miner" 

 excursion a considerable proportion belong to what may be termed 

 the C. inerme group of Haeckel's sub-genus C oUodinium — forms 

 in which the prevailing shape of the zooid is spherical, and in 

 which there is a single, relatively large, oil-globule. All the lead- 

 ing modifications and phases are represented — except that there 

 are none in which a capsular membrane can positively be said to 

 be absent. 



Until further material has been obtained I think it better to 

 defei' any attempt to deal systematically with this group. But 



1 Witli the exceptions to be referred to later. 



- Haec-kel, E— Die Radiolarien. Eine Monographie, 1862., p. 522. 

 « Haeckel, E— The Radiolaria. Cliall. Eep., Zool.. xviii., 1887, p. 25. 

 ^ Brandt, K — Die Koloniebildende Radiolarien : Sphaerozoen, (Fauna u. 

 Flora Grolfes t. Aeapel, xiii., 1888., ]i. 6.) 



