REPORT ON THE RADIOLARIA. 1597 



branches, which are partly confluent and fenestrated (similarly as in PI. 107, fig. 1), but not 

 forming an outer lattice-shell. Meshes irregularly polygonal. 



Limensioiis. — Diameter of the shell o'3, length of the spines 6 to 9, breadth 0'03. 



HaMtat. — Tropical Atlantic, Station 347, depth 2250 fathoms. 



11. Orosphcera arborescens, n. sp. (PI. 106, fig. 3). 

 Orothamnus arborescens, Haeckel, 1881, Atlas, loc. cit. 



Radial spines cylindrical, rough, more or less curved, somewhat longer than the diameter of 

 the subspherical or slightly ellipsoidal shell, and at the thicker base three times as broad as its 

 smooth bars, bearing numerous irregularly branched and curved, sometimes confluent, lateral 

 branches. j\Ieshes irregularly quadrangular. 



Dimetisions. — Diameter of the shell 1'2 to 1-6, length of the spines 1-5 to 2'2, breadth 0'06. 



HaUtat. — South Atlantic, Station 335, depth 1425 fathoms. 



Geuus 673. Oroscena,^ n. gen. 



Definition. — r o s p h se r i d a with a simple, polyhedral or subspherical lattice- 

 shell, and with numerous pyramidal elevations on its surface, the top of which bears a 

 radial spine. 



The genus Oroscena differs from the preceding Orosphcera in the possession of 

 numerous pyramidal or tent-shaped elevations, each of which bears on its top a radial 

 spine. It exhibits therefore the same relation to the latter that Sagoscena does to 

 Sagosphcera and Auloscena to Aulosphcera. The bases of the radial spines are usually 

 connected by prominent concave crests, the edges of the pyramids. The species 

 described of Oroscena seem to be very variable and transformistic. 



Subgenus 1. Oroscenium, Haeckel. 



Definition. — Radial spines simple, smooth or spiny, but neither branched nor 

 forked. 



1. Oroscena gegenhauri, n. sp. (PL 106, fig. 4). 



Radial spines club-shaped, about half as long as the radius of the shell, cylindrical and finely 

 sulcata in the basal third, ovate and elegantly dimpled in the distal two-thirds. The bases of the 

 radial spines are connected by prominent concave crests, which form the edges of the polyhedral 

 shell. Meshes irregularly polygonal, the majority quadrangular, separated by denticulate bars. 



1 Oroscena = Shell witli tent-ahaped elevations ; ogoj, ff«n»ij. 



