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



the capsule one single very large spiculum, whilst the others are much smaller (fig. 3). All the 

 alveolated capsules are placed in one single stratum on the surface of the jelly-like spherical 

 cosnobium, comparable to the blastoderm-cells of a blastula. 



Dimensions. Diameter of the central capsules 0'08 to 01, of the alveoles 0'2 to 0'4, length of 

 the spicula 01 to 0'3. 



Habitat. South Pacific (Juan Fernandez), Station 300, surface. 



12. Sphcerozoum verticillatum, n. sp. (PI. 4, fig. 7). 



Spicula all geminate-triradiate, with a short simple middle rod and three much longer arborescent 

 shanks on each end of it. Shanks straight, slender, pine-shaped, each in the distal half with three 

 to four elegant verticils of thorny lateral branches. 



Dimensions. Diameter of the capsules 01 to 012, middle rod of the spicula - 03 to 0'05, 

 shanks 01 to 015. 



Habitat. Indian Ocean, Ceylon, Haeckel ; Madagascar, Eabbe ; surface. 



13. Sphcerozoum octoceras, n. sp. 



Spicula all geminate-quadriradiate, with a short simple middle rod and four diverging shanks on 

 each end of it. Shanks smooth, irregularly curved or bent, three to six times as long as the middle 

 rod. It may be regarded as the social form of Thalassoxanthium octoceras (PI. 2, fig. 6). 



Dimensions. Diameter of the capsules 012 to 016, middle rod of the spicula 0'02, shanks 

 O'Ol. 



Habitat. Australia, south coast, Faber; Station 163, surface. 



14. Sphcerozoum quadrigeminum, n. sp. 



Spicula all geminate-quadriradiate, with a long thick middle rod and four shorter diverging 

 shanks on each end of it. Shanks straight, thorny. 



Dimensions. Diameter of the capsules 0'06 to 0'08, length of the spicula 0'05 to 015. 

 Habitat. North Atlantic, Azores, Station 354, surface. 



15. Sphcerozoum araucaria, n. sp. 



Spicula all geminate-quadriradiate, with stout straight middle rod and four longer diverging 

 shanks on each end of it. Shanks arborescent, with six to twelve thorny lateral branches. 

 Dimensions. Diameter of the capsules 01 to 015, length of the spicula 0'05 to 01. 

 Habitat. South Atlantic, coast of Brazil, Eabbe ; surface. 



16. Sphcerozoum arbor escens, n. sp. (PL 4, fig. 8). 



Spicula all geminate-quadriradiate, with a stout straight middle rod and four longer diverging 

 shanks on each end of it. Shanks arborescent, pine-shaped, with four to six verticils of lateral 

 branches, which again are ramified and thorny. 



