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



a deer-horn, one-fourth to one-half as long as the radius of the shell. Some other small spines 

 irregularly scattered over the shell. 



Dimensions. Diameter of the shell 012 to 016, of the smaller pores O'OOl to 0'004, of the. 

 larger armed pores 0'016 to 0-024 ; length of the spines 0'02 to 0'04. 



Habitat. Central area of the Tropical Pacific, Stations 266 to 272, depth 2425 to 2925 

 fathoms. 



Genus 36. Siphonosphcera, 1 J. Muller, 1858, Abhandl. d. k. Akad. d. Wiss. 



Berlin, p. 59. 



Definition. C ollosphserida with simple shells, the pores of which are pro- 

 longed into external simple radial tubuli with solid wall ; outer mouth of the tubuli 

 truncated, smooth. 



The genus Siphonosphcera is, next to Collosphcera, the most common of all Collo- 

 sphaerida, and rich in different species ; all agreeing in the tubular prolongation of the 

 pores, and corresponding therefore to Ethmosphcera among the simple Liosphserida. 



Subgenus 1. Holosiphonia, Haeckel. 

 Definition. All the pores or apertures of the shell prolonged into tubules. 



1. Siphonosphcera pansiphonia, n. sp. 



Shell a regular sphere, everywhere occupied by short, regular cylindrical tubes, all of the s*ame 

 size and form. Length of the tubules equal to their breadth and to the intervals between them. 

 Ten to twelve tubules in the half meridian of the shell. This most regular species is nearly allied 

 to Collosphcera regularis, and may be derived from it by tubular prolongation of all the regular 

 pores. 



Dimensions. Diameter of the shell 01 to 012, length and breadth of the tubules 0'005 

 to 0-006. 



Habitat. -Indian Ocean, Sunda Strait, Rabbe, surface. 



2. Siphonosphcera marginata, n. sp. 



Shell a regular or subregular sphere, occupied by numerous short cylindrical tubules of different 

 sizes. Six to eight tubules in the half meridian of the shell. Diameter of the tubules about equal 

 to their distance apart, but two to four times as large as their length. 



Dimensions. Diameter of the shell 01 to 14 ; length of the tubules 0'004 to 0'006, breadth of 

 the tubules and the intervals O'Ol to 0'02. 



Habitat. Central Pacific, Station 268, depth 2900 fathoms. 



1 Siphonosphcera = Sphere with tubes ; a!<foy, <7?i. 



