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



7. SiphonosphcBra conifera, n. sp. (PI. 6, fig. 9). 



Shell subspherical, everywhere occupied by irregular conical tubules, the length of which nearly 

 reaches the shell radius. Inner aperture of the cones two to three times as large as the outer. 

 Four to five tubules in the half meridian of the shell. Distances between the bases of the cones small 

 and irregular. 



Dimensions. — Diameter of the shell 0-06 to 0-08, length of the tubules O'OS to 0-04 ; inner aperture 

 of the cones 0-01 to 002, outer aperture 0008 to 001. 



Habitat. — Indian Ocean, Cocos Islands, Eabbe, surface. 



8. Siphonosphcera fragilis, n. sp. 



Shell quite irregular roundish or nearly ovate, very thin and fragile, everywhere occupied by 

 irregular, short, and broad cylindrical or conical tubes. Six to ten tubes in the half meridian of the 

 shell. Diameter of the tubules about one-eighth that of the slieU, three to four times as large as 

 the length of the tubules, and the distance apart of their bases. 



Dimensions. — Diameter of the shell 016 to 0'24, of the tubules 002 to 0'03 ; length of the 

 tubules 0006 to 0008, distance of them 0-005 to 0009. 



Habitat. — East coast of Australia, Sydney, Faber ; Station 165, s-nrface. 



Subgenus 2. Merosiphonia, Haeckel. 

 Definition. — Only part of the shell apertures prolonged in tubules, the others simple. 



9. Siphono.^phcera socialis, n. sp. (PI. 6, figs. 1, 2). 



Shell a regular or subregular sphere, bearing only a small number (one to four, commonly two 

 to tliree) of short and liroad cylindrical tubules, irregidarly scattered. Between them many small 

 circular or subcircular pores of different sizes, double as broad as their bars. Eight to ten pores in 

 the half meridian of the sheU. Tubules three to six times as broad as the pores, about as long as 

 broad, now quite cylindrical, now somewhat dilated at the outer opening. (Although the shells and 

 cells of this common species are among the smallest, their colonies are among the largest, often 

 containing more than one hundred social individuals, often enclosed in alveoles.) 



Dimensions. — Diameter of the shell 0-04 to 0-05, of the pores 0-002 to 0-004, of the tubules 

 0-015 to 0-02 ; length of them about the same. 



Habitat. — Tropical and subtropical part of the Eastern Atlantic, Cape Verde Islands, Canaries, 

 very common, Haeckel ; Stations 338 to 353, surface. 



10. Siphonosphcera polysiphonia, n. sp. 



SheU a regular or subregular sphere, bearing twelve to sixteen circular pores in its half meridian. 

 Nearly one half the pores simple, very small ; the other half prolonged into short cylindrical tubules, 



