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



Dimensions. — Diameter of the shell 009 to Oil, of the pores 0-002 to 0004, of the bars 

 003 to 0-006 ; length of the tiibuli 0'05 to 006 ; diameter of the inner aperture 0'02 to 003, of 

 the outer aperture 005 to 0'07. 



Habitat. — Western part of the South Atlantic, Station 325, surface. 



Genus 41. Otosphcera,^ n. gen. 



Definition. — Collo sph ser ida with simple shells, the pores of which are pro- 

 longed into external simple radial tubuli with fenestrated walls ; outer mouth of the 

 tubuU armed with a single tooth. 



The genus Otosphcera differs from SolenosphcBra by the single tooth on the external 

 mouth of the tubuli, from MazosphcBra by the fenestration of the walls of the tubuli. 



1. Otosphcera polymo7pha, n. sp. (PI. 7, fig. 6). 



Shell quite irregular, polyhedral or roundish, very variable in size and form, with numerous very 

 small pores, much smaller than the bars. Twenty to thirty pores in the half meridian of the shell. 

 Porous tubuli of the shell commonly in variable number (one to four), but sometimes constant in 

 number (one, two, three, or four) in the one and same colony. TubiJLi irregular conical, 

 commonly about as long as the radius of the sheU ; their outer aperture obliquely truncated, on one 

 side prolonged into one large, prominent, bill-hke, curved, acute tooth. 



Dimensions. — Diameter of the shell 0-12 to 0-15, of the pores 0-001 to 0002 ; length of the 

 tubuli 006 to 008, inner aperture 0-03, outer aperture 0-02. 



Habitat. — Indian Ocean, Madagascar, Eabbe, surface. 



2. Otosphcera auriculata, n. sp. (PI. 7, fig. 5). 



Shell quite irregular, of extremely variable form, now inclining to roundish, now to polyhedral, 

 with very numerous small pores, irregularly formed and distributed. Twelve to twenty-four pores 

 iu the half meridian of the shell, of very different size, for the most part larger than the bars. Porous 

 tubuli of the shell of variable number (in one and the same colony), one to five, mostly three or 

 four, of conical form, ii-regularly formed and scattered, commonly about half as long as the radius 

 of the shell. Outer aperture of the tubuU obliquely truncated, with one large prominent, often 

 curved, acute tooth. 



Dimensions. — Diameter of the shell O'l to 0-2, of the pores 0-003 to 0-005 ; length of the tubuli 

 001 to 005, inner aperture 0-04, outer aperture O'OS. 



Habitat. — Central Tropical Pacific, Stations 268 to 272, depths 2425 to 2925 fathoms. 



1 Oiosp/iara = Shell with ears ; cTtm^ai'^a.. 



