Vol. 55.] DEVONIAl^" KOCKS OF NEW SOUTH WALES. 43 



tests of the radiolaria are less frequently shown than the inner 

 or medullary tests. The forms in the tuff are best preserved ; 

 those in the limestones are usually so thickly mingled together 

 that their characters are often hidden, while the chert forms, being 

 casts merely without structure, are of no use for systematic de- 

 scription. The classification of Haeckel, as given in his Challenger 

 Report on the Radiolaria,^ has been followed. 



The measurements given are in millimetres and decimal parts, 

 and the figures in the plates are all drawn to the same scale of 

 200 diameters. As the radiolaria are all from Tamworth and 

 belong to the same series of Devonian rocks, the locality and 

 formation are not repeated with each species, and only the numbers 

 of the beds are given. The slides containing the figured specimens 

 are in my own collection. 



Class RADIOLARIA, MiiUer. 



Subclass SPUMELLARIA, Ehrenberg. 



Order BELOIDEA, Haeckel. 



Genus Sph^rozoum, Meyen. 



The skeleton consists of free siliceous spicular bodies of various 

 forms. 



Sph^eozoum sp. (PI. YIII, figs. 1 a-1 e.) 



The only spicules of this genus which have been observed are very 

 minute, apparently three-rayed forms ; the rays are short and have 

 either rounded or truncate terminations, or they are club-shaped. 

 They range between 0*03 and 0*04 mm. in diameter. They have the 

 same glistening appearance as that already noticed in these spicules 

 from other deposits. They occur detached and very sparingly, both 

 in the dark siliceous limestones and in the volcanic tuffs. Nos. 4, 

 245 3, 387 D. Similar forms have been found in nearly all radio- 

 larian rocks from the Cretaceous downwards. 



Order SPH^ROIDEA, Haeckel. 

 Genus Cenosph^ra, Ehrenberg. 



The test is a simple latticed sphere, without radial spines. 

 Cen^osph^ra scitula, sp. nov. (PI. VIII, fig. 2.) 



Test small, with delicate narrow lattice-bars ; the pores are some- 

 what subangular and unequal ; in the angles are very minute 

 spines. Diameter of test, 0-09 mm. ; of the pores, 0-01 mm. Rare, 

 In siliceous limestone, l^o. 24^5 3. This form corresponds in size 

 with C. minuta, Pantanelli, but according to Dr. Riist ^ the pores 

 in this latter are only about half the size of those in C. scitula. 



^ Zoology, vol. xviii (1887). 



2 Palseontographica, vol. xxxiv (1888) p. 190. 



