REPORT ON THE RADIOLARIA. 1637 



Genus 690. Aidodictyum, 1 Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, 



Dec. 12, p. 6. 



Definition. A ulosphserida with polygonal meshes in the network, the tubes 

 of which are connected in different directions and form the spongy wall of a spherical 

 shell. No radial tubes prominent over the surface. 



The genus Aulodictyum differs from Aulonia, its ancestral form, in the develop- 

 ment of a spongy framework in the thickened wall of the spherical lattice-shell. It 

 bears therefore to the latter the same relation as Auloplegma does to Aularia. But 

 the outer surface of the hollow sphere is in Aulodictyum completely smooth, as well as 

 the inner, and bears no radial tubes. Only one species of this genus has been observed. 



1. Aulodictyum hydrodictyum, n. sp. 



Shell spherical, smooth on the outer and inner surfaces, composed of an irregular framework of 

 straight and smooth cylindrical tubes ; its meshes very irregular, of unequal size and various forms. 

 The diameter of the sphere is about six or eight times as great as the thickness of its reticular 

 wall. 



Dimensions. Diameter of the sphere 2 to 3, of its meshes 01 to 0'2 ; breadth of the bars 

 O'Ol. 



Habitat. Antarctic Ocean, Station 157, depth 1950 fathoms. 



Family LXXYII. CANNOSPH^RIDA, Haeckel (PL 1 1 2). 



Cannosplicerida, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. G. 



Definition. PH^ODARIA with two concentric spherical or subspherical shells, which 

 are connected by numerous thin, tubular, radial beams. Inner shell simple, spherical or 

 ovate, solid or latticed, with a peculiar mouth. Outer shell spherical or polyhedral, 

 articulate, composed of hollow tangential tubes, which are separated by astral septa at 

 the stellate nodal points. From the latter arise hollow radial tubes, whilst the inner 

 radial beams, connecting the two shells, are inserted in the middle of the tangential tubes. 

 No peculiar mouth in the outer shell. Central capsule enclosed by the inner shell. 



The family Cannosphserida comprises a small number of remarkable PH.EODARIA 

 which are rare and found only in a few localities. They differ from all the other 

 PH.EODARIA in the possession of two concentric spherical shells, which are connected by 

 radial beams, and the inner of which is quite simple, like that of the Medusettida, 



1 Aulodictyum = T\i\m\a.r net ; ixo',-| 



