262 THE VOYAGE OF H.M.S. CHALLENGER. 



Subgenus 2. Cromyoimnura, Haeckel. 

 Definition. — Pores of the outer cortical shell irregular, of different size and form. 



4. Cromyomma perspicimm, n. sp. (PI. 30, fig. 8). 



Cromyosphfera 2'>erspicua, Haeckel, 1879, Atlas (pi. .xx.x. fig. 8). 



Eadial proportion of the four shells = 1 : 2'5 : 6 : 9. Outer cortical shell very thin walled, witli 

 thread-like bars, and irregular, polygonal pores; inner cortical shell with similar pores, liut witli 

 thicker bars. Both medullary shells with regular, circular pores (the outer three times as broad as 

 the inner). Numerous thin radial beams connect the latter with the former ; other very thin and 

 numerous beams connect the two cortical shells, and are pi'olonged outside into short bristle- 

 shaped spuies (often longer than in the figure). 



Dimensions. — Diameter of the four shells — (A) OlS, (B) 0-12, (C) 0-05, (D) 0-02; pores of the 

 outer shell 0-01 to 0-02 ; length of the spines Q-Ql to 0-03. 



Sahitat. — Central Pacific, Station 274, surface. 



5. Cromyomma quadruplex, Haeckel. 



Cromijomma qiiadruplex, Haeckel, 1862, MoDOgr. d. Kadiol., p. 44:6. 



Haliomma quadruplex, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. d. Wiss. Berliu, p. 243. 



Eadial proportion of the four spheres = 1 : 3 : 7 : 10. Outer cortical shell thin walled, irregularly 

 covered with numerous angular spines, as long as the radius. Pores of all four shells irregular 

 roundish, increasing in size from the first to the fourth. 



Dimensions. — Diameter of the four shells — (A) 0-15, (B) 01, (C) 0-045, (D) 0-015; pores of tlie 

 outer shell O'Ol to 0-02 ; length of the spines 0-07. 



Habitat. — North Atlantic, Station 353, depth 2965 fathoms. 



6. Cromyomma macroporum, Stohr. 



Cromijomma macroporum, Stohr, 1880, Palajontogr., vol. xxvi. p. 95, Tuf. iii. fig. 4. 



Eadial proportion of the four spheres = 1 : 3 : 6 : 9. Outer cortical shell thick walled, densely 

 covered with short conical spines, as long as the diameter of the pores ; the latter are irregular, 

 roundish, or polygonal, larger and smaller alternating. 



Dimensions. — Diameter of the four shells— (A) O'l, (B) 0-0G6, (C) 0-033, (D) 0-011 ; pores of 

 the outer shell 0-033 to 0-016, bars 0-003 ; length of the spines 0-01. 



Habitat. — FossU in the Tertiary rocks of Sicily, Grotte, Stohr. 



7. Cromyomma circumtextum, n. sp (PI. 30, fig. 4). 



Eadial proportion of the four spheres =1:2:5:7. Outer cortical shell very delicate ami thin 

 walled, with thread-like bars and large, irregular, polygonal meshes (larger than the innermost shell); 



