REPORT ON THE RADIOLARIA. 1031 



2. Auloplegma spongiosum, n. sp. (IM. Ill, fig. 9). 



Kadial tubes slender, straight, cylindro-couical, studded irregularly with lateral branches, which 

 are short, simple, sliglitly curved, partly vertieillate in the distal third, and ending with a small 

 spinulate knob. The length of the radial tubes is about twice as great as the radial diameter of the 

 spongy framework, which forms the wall of the spherical shell, and is composed of thorny or verti- 

 eillate cylindrical tubes. 



Dimcnsio7is. — Diameter of the shell 3'2, of its wall 01 ; length of the radial tubes 0'24, 

 breadth 001. 



Rahitat. — North Pacific, Station 231, surface. 



Genus 686. Axdophacus,^ n. gen. 



Definition. — A u 1 o sph 33 ri da with triangular meshes in the network, the 

 tangential tubes of which form a simple, lenticular, biconvex lattice-shell, with 

 shortened vertical main axis. Radial tubes arise at its nodal points. 



The genus Aulophacus differs from the common Aulos2)h(era, its ancestral form, 

 only in the lenticular comj^ression of the spherical lattice-shell, the vertical axis of 

 which is considerably shortened. It exhibits therefore to the latter the same relation 

 as Cenodiscus does to Cenosp>]i(Bra among the Sphasroidea. The contrary condi- 

 tion is shown in the following genus Atdatractus, in which the vertical axis is prolonged. 

 In the two species of Aidophactts observed the radial spines exhibit a remarkable 

 peculiarity, being longer on the circular periphery of the lens, shorter on both its faces, 

 and shortest in the vertical main axis. 



1. Aidophacus lenticularis, u. sp. (PL 111, fig. 5«). 



Shell biconvex, lenticular, with rounded circular margin ; its horizontal diameter three times 

 as great as its thickness (or its vertical main axis). Eadial tubes cylindro-conical, straight, with 

 six to nine triradiate verticils, those of the margin of the lens twice as long as the smooth tangential 

 tubes, the others shorter. 



Dimensions. — Horizontal diameter of the lens 5T) mm., vertical main axis 0'2 ; length of the 

 radial tubes 0-2, breadth O'Ol. 



Habitat. — Indian Ocean, Belligemma, Ceylon (Haeckel) surface. 



2. Aidophacus amphidiscus, n. sp. (PI. Ill, fig. 5b). 



Shell discoidal, slightly biconvex, with rounded circular margin ; its horizontal diameter five 

 times as great as its thickness. Eadial tubes cylindrical, covered with numerous short thorns, those 

 of the margin of the lens three times as long as the smooth tangential- tubes, the others shorter. 



' Aulophacus = Tnhula.T lens ; ctvT^o;, <p»y.i;. 



