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



2. Belonozoum spinulosum, Haeckel. 



Sphcerozoum spinulosum, J. Muller, 1858, AbhandL d. k. Akad, d. Wiss. Berlin, p. 54, Taf. viii. 



fig. 4. 

 Sphoei-ozoum spinulosum, Haeckel, 1862, Monogr. d. Radiol., p. 527, Taf. xxxiii. figs. 3, 4. 



Spicula all simple rods, straight cylindrical, obtuse on both ends, thorny with numerous small 

 spines, placed vertically on the rods. 



Dimensions. Diameter of the central capsule 0'08 to 01, length of the spicula 0'05 to 0'2. 

 Habitat. Mediterranean, Nice, J. Muller ; Messina, Haeckel ; Naples, Brandt ; surface. 



3. Belonozoum italicum, Haeckel. 



Sphcerozoum italicum, Haeckel, 1862, Monogr. d. Radiol., p. 526, Taf. xxxiii. figs. 1, 2. 



Spicula all simple rods, more or less curved or bent, pointed at both ends, quite smooth. 

 Central capsule with a variable number (commonly five to twenty) of oil-globules. 



Dimensions. Diameter of the central capsule O'l to 0'3, length of the spicula 0'05 to 0'2. 

 Habitat. Mediterranean, Nice, Naples, Messina, Haeckel, surface. 



4. Belonozoum atlanticum, n. sp. 



Sphcerozovm atlanticum, Haeckel, 1881, Manuscript. 



Spicula all together simple rods, more or less curved or bent, pointed at both ends, thorny 

 from numerous small spines, placed vertically on the rods. 



Dimensions. Diameter of the central capsule O'l to 0'2, length of the spicula O'OV to O'l 5. 

 Habitat. Tropical Atlantic, Station 348, surface. 



Genus 13. Sphcerozoum, 1 Meyen, 1834, Nova Acta Acad. Nat. Curios., Bd. xvi., 



Suppl., p. 287 (p. 163). 



Definition. S phaerozoida with branched or radiate spicula of one kind. 



The genus Sphcerozoum, with Physematium one of the two oldest Radiolaria, observed 

 in the living state, was founded 1834 by Meyen for one of the social B e 1 o i d e a, which 

 was probably the common cosmopolitan Sphcerozoum punctatum, the true type of this 

 genus. Johannes Muller described a number of species, which were partly skeletonless 

 (Collozoum), partly armed with simple or with compound spicula. The species with 

 simple spicula we refer here to Belonozoum, the species with two or more different 

 kinds of spicula to Rhaphidozoum, while we unite in Sphcerozoum all species with one 

 kind of branched or compound spicula. 



1 SphiETOZoum = Spherical animal ; 



