96 THE VOYAGE OF H.M.S. CHALLENGEE. 



Dimensions. Diameter of the shell 01 to 012, of the pores 0002 to O'OOS, breadth of the 

 bars 0-004 to O'OOS. 



Habitat. Tropical and subtropical zone of both hemispheres, widely distributed ; Canaries, 

 Azores, Cape Verde Islands, Guinea Coast, Brazil Coast, Indian Ocean, Madagascar, Ceylon, surface. 



Subgenus 2. Dyscollosphcera, Haeckel. 



Definition. Shell not a regular sphere, but irregular roundish, in all degrees of 

 variation between subspherical and polyhedral or quite irregular forms. 



4. Collosphcera huxleyi, J. Miiller. 



Collosphcera huxleyi, J. Miiller, 1855, Abhandl. d. k. Akad. d. "Wiss. Berlin, pp. 55-59, Taf. viii. 



figs. 6-9. 



Collosphcera huxleyi, Haeekel, 1862, Monogr. d. Eadiol., p. 534, Taf. xxxiv. 

 Collosphiera huxleyi, Cienkowski, 1871, Arctriv f. mikrosk. Anat., Bd. vii. p. 374, Taf. xxix. 



figs. 1-6. 



Collospheera ligurina, J. Miiller, 1856, Monatsber. d. k. Akad. d. Wiss. Berlin, p. 481. 

 Thalassieolla punetata, var., Huxley, 1851, Ann. and Mag. Nat. Hist., ser. 2, vol. viii. p. 434, 



pi. xvi. fig. 6. 



Shell subspherical, somewhat irregular, sometimes with more or less superficial impressions, 

 with irregular network of roundish meshes. Eight to sixteen meshes in the half meridian of the 

 shell, one to three times as broad as their bars. Very variable, with direct transition-forms to other 

 species of this genus, especially to Collosphcera globularis, Collosphcera tuberosa, Collosphcera pyriformis, 

 and Collosphcera polyedra. 



Dimensions. Diameter of the shell 01 to 016, of the pores 0'004 to 0'012, of the bridges 

 0-003 to 0-006. 



Habitat. Cosmopolitan ; common in the greater part of the warmer seas, surface. 



5. Collosphcera polygona, n. sp. (PI. 5, fig. 13). 



Collosphtera huxleyi var., Haeckel, 1862, Monogr. d. Kadiol., Taf. xxxiv. fig. 5. 



Shell irregular polygonal, with very delicate, irregular network of polygonal meshes, four to 

 twelve times as broad as the bars. Ten to twenty pores on the half meridian of the shell. 



Dimensions. Diameter of the shell 01 to 0'2, of the pores 0'012 to 0'004, of the bars O'OOl 

 to 0-002. 



Habitats Mediterranean, Atlantic, surface; Stations 348 to 354. 



6. Collosphcera pyriformis, Haeckel, n. sp. 



Shell irregular, rounded, ovate or pear-shaped, with irregular network of rounded or nearly 

 polygonal meshes. Ten to twenty meshes in the half meridian of the shell, one to three times as 

 broad as the bars. Commonly one large opening (two to three times as broad as the largest 



