REPORT ON THE RADIOLARIA. 1615 



short, divergent, apical spines which are forked at the distal end. (Very similar to Sagoscena castra 

 and Sagoscena tcntorium, PI. 108, figs. 1, 6, probably derived from them, but differing in the 

 spongy structure of the thickened shell-wall, which is half as thick as the radius of its cavity.) 



Dimensions. Diameter of the sphere 2'0 to 2'5, length of the bars 015 to 0'2, breadth 0'002. 



Habitat. North Pacific, Stations 231 to 239, surface. 



2. Sagoplegma scenophora (PL 108, fig. 13). 



Pyramids on the surface of the spongy sphere irregular, with three to six sides, unequal in size 

 and different in form. The edges of each pyramid are prolonged over its top into three to six 

 divergent apical spines, which bear three to six cruciate verticils, each composed of four small, 

 crossed, lateral branches, armed with a spinulate knob at the distal end. 



Dimensions. Diameter of the sphere 3'0 to 3'5, length of the bars - 25 to 0'35, breadth 0'003. 



Habitat. North Pacific, Stations 252, 253, surface. 



Family LXXVI. AULOSPH^RIDA, Haeckel (Pis, 1 09- 111). 



Aulosphcerida, Haeckel, 1862, Monogr. d. Radiol., p. 357. 



Definition. PELEODARIA with a large spherical or subspherical (rarely spindle- 

 shaped) articulated shell, which is composed of hollow tangential tubes. Nodal points 

 of the loose network stellate, with a nodal cavity and astral septa. Meshes either 

 triangular or polygonal. Hollow radial spines arise usually at the nodal points of the 

 surface. No peculiar mouth in the shell. Central capsule tripylean, placed in the centre 

 of the shell. 



The family Aulosphaerida comprises a great number of splendid and widely distri- 

 buted PH^EODARIA, which have a special interest on account of the peculiarly complicated 

 structure of their large lattice-shell, of the extraordinary beauty of their form and of 

 their remarkable relations to the other PH^EODARIA. They differ from all the other 

 Radiolaria in the peculiar articulate composition of the spherical skeleton of hollow 

 tangential tubes, which are connected (and at the same time separated) by sutural or 

 astral septa and filled up by jelly. The same peculiar structure recurs only in the 

 closely allied Cannosphserida, which, however, differ in the possession of a second internal 

 concentric shell, connected with the outer by radial beams. The similar Sagosphserida, 

 which exhibit corresponding forms in various genera, differ from the Aulosphasrida in 

 the simpler structure of the delicate lattice-sphere, which is composed of very thin solid 

 threads of silica, without astral septa. The Orosphaerida, finally, also nearly related to 

 the preceding families, differ from them in the coarse structure of the lattice-sphere, 

 which is composed of very thick tangential, concentrically stratified rods, with an 

 internal axial canal, but without astral septa at the nodal points. 



