RECENT RESEAUCHES OiST THE RADIOLARIA. 



149 



detached parts. Now if we conceive these to be united together 

 into one complex structure, we may thence derive all the other 

 forms of circumferential Eadiolarian skeletons. First, by union 

 in an irregular manner, we obtain a spheroidal investing network 

 with irregular intervals, as in Gyrtidosplicera and Gollosplicera. 



Secondly, let these be united with regularity, and we get such 

 a form as Heliosplicsra inermis * (the skeleton of which consists of 

 bars enclosing equal-sized and perfectly regular hexagonal spaces); 

 and if the skeletal parts be hollow, we get such a structure as 

 Aulosphaera elegantissima \. 



Thirdly, let the intervals of the network be greatly reduced in 

 relative size, as sometimes in Gollosplicera X, and the sphere be 



Fig. 6. 



BicfyopocUiim, sp. ? (After Wyv. Tliomson.)§ 



* L. c. pi. ix. fig. 1 . t L. c. pi. xi. fig. 6. | L. c. pi. xxxIy. fig. 4. 



§ I herewith take the opportunity of acknowledging the kindness of Prof. Sir 

 C. Wyville Thomson and Messrs. McMillan & Co., in allowing me the use of 

 woodcuts fig. 6 and fig. 8 hereafter represented. Both these haye already 

 appeared in the ' Voyage of the Challenger.' 



