EEPORT ON THE EADIOLARIA. 831 



radial spines, each of which bears four crossed apoj^hyses. The subfomily may be 

 divided into two different tribes, the Stauraspida and Lychnaspida. In the Staura- 

 spida either all twenty spines, or a part of them, bear no perforated plates, and the 

 shell is composed wholly or partially of the meeting branches of their apophyses. 

 In the Lychnaspida, however, the four apophyses of each single spine form, by reunion 

 of their recurved branches, a plate or shield wdth four crossed aspinal pores. The 

 Lychnaspida represent therefore a more developed stage in the shell-formation than 

 the simpler Staurasjaida. Staurusjyis, as the common ancestral form of both, may be 

 derived phylogenetically from Xii^hacantlia or Stauracantha, which differ only 

 I)}" the apophyses or branches of the apophyses not meeting. These branches (originally 

 eight on each spine) are either simple or again branched. 



Subgenus 1. Staurasparium, Haeckel. 



Definition. — Apophyses of the spines simple, not branched; therefore each spine 

 with four sutural condyles. 



1. Stauraspis cruciata, n. sp. (PI. 134, fig. 5). 



Eadial spines thin, quadrauc^ulai', prismatic ; outer and inner half nearly of equal length. 

 Central bases pyramidal, with wing-like edges fig. 5). Four apophyses of each spine simple, not 

 branched, with thin condyles. Large meshes of the shell ten to twenty times as broad as the 

 bars. This and the following species greatly resemble the simplest forms of Phradaspis 

 (PL 137, figs. 1, 2) ; they differ from these, however, by the equal size and distance of the four 

 branches of each spine, which thus form a rectangular cross. 



Dijncnsions. — Diameter of the shell O'l ; breadth of the spines and bars 0"002. 



Habitat. — Central Pacific, Station 268, surface. 



2. Stauraspis xipliacantha, n. sp. 



Eadial spines stout, cylindrical in the inner half, conical in the shorter outer half. Pour 

 apophyses of each spine simple, not branched, broad, with thick condyles. Meshes of the shell 

 six to eight times as broad as the bars. 



Dimc7isio7is. — Diameter of the shell 012 ; breadth of the spines and bars O'OOS to O'Ol. 



Habitat. — South Pacific, Station 290, surface. 



Subgenus 2. Stauraspidium, Haeckel. 



Definition. — Apophyses of the spines branched; therefore each spine with eight to 

 twenty or more sutural condyles. 



