REPORT ON THE RADIOLARIA. 1287 



The genua CUstophana agrees with the ]3reeeding SctlMphcena in the mouth of the 

 thorax being closed by a L'lttice-phite. But the appendages of the thorax are terminal 

 feet, not lateral wings; their number is commonly six or nine, rarely more. ClistojjJto'na 

 may be derived either from Tetrahedrina by interpolation of secondary feet between 

 the three primary, or from Scthamphora by development of a basal lattice-plate closing 

 the mouth. 



1. ClistophcBua riistiana, n. sp. (PI. 57, fig. 6). 



Shell rough, with distinct collar stricture. Length of the two joints = 3 : 10, breadth = 4 : 11. 

 Cephahs hemispherical, with small, circular pores and a stout oblique horn three times the length, 

 which is three-sided prismatic, and at the top denticidate. Thorax subconical, inflate, with 

 regular, circular, quincuncial pores, increasing in size towards the base. Margin of the flat base, 

 with six divergent, stout feet of the same prismatic form as the cephahc horn, with denticulate 

 distal ends, about as long as the thorax. This elegant species is dedicated to Dr. Elist of Freiburg, 

 the discoverer of numerous fossil Eadiolaria in the Liassic and Jurassic formations. 



Dimensions. — Cephahs 0'03 long, 0"04 broad ; thorax 0"1 long, Oil broad. 



Habitat. — Central Pacific, Station 265, depth 2900 fathoms. 



2. Clistophcena hexolena, n. sp. 



Shell smooth, with shght collar stricture. Length of the two joints =1 : 4, breadth =1 : 5. 

 Cephahs subspherical, small, with a large, vertical, cylindrical horn, about as long as the shell, 

 and small, circidar pores. Thorax nearly three-sided pyramidal or tetrahedral, with three 

 rounded edges and subregidar, cu-cular pores. Margin of the flat base with six conical, divergent 

 straight feet, somewhat shorter than the thorax. (Three on the corners, one on the middle of each 

 side of the triangular base.) 



Diinensions.- — Cephalis 0'03 diameter, thorax 0'12 long, 0'14 broad. 



Habitat. — North Pacific, Station 241, depth 2300 fathoms. 



3. ClistophcBna pyramidalis, u. sp. 



Shell smooth, with shght collar stricture. Length of the two joints = 2 : 8, breadth = 3 : 10. 

 Cephalis hemispherical, with a stout pyramidal horn of twice the length. Thorax six-sided 

 pyramidal, with regular, circular pores of equal size, and six prominent, straight edges, which are 

 prolonged into six divergent, pyramidal feet of half the length. 



Dimensions. — Cephahs 0-02 long, 0'03 broad ; thorax 0'08 long, 01 broad. 



Habitat. — Central Pacific, Station 274, depth 2750 fathoms. 



