REPORT ON THE RADIOLARIA. 31 



I described these two different species, the new Thalassosphcera bifurca and the 

 Thalassosphcera morum, which J. Miiller had formerly called Ttialassicolla morum. 

 This latter form is characterised by peculiar calcareous bodies " looking in outline like the 

 rowels of spurs, scattered irregularly in the gelatinous envelope," and was therefore 

 afterwards called "Calcaromma calcarea" by Sir Wyville Thomson. 1 As already men- 

 tioned above, these calcareous rowels are foreign bodies, picked up by an Actissa 

 (seep. 29). I here confine the genus Thalassosphcera to those solitary B el o id e a 

 in which the body exhibits no alveoles, and the siliceous solid spicula in the calymma 

 are quite simple needles. 



Thalassosphcera belonium, n. sp. 



Spicula thin cylindrical rods, more or less curved, pointed at both ends, with smooth surface 

 (similar to the needles of Rliaphidozoum italicum). Central capsule spherical, three times as large 

 as the central nucleus, without larger oil-globules. 



Dimensions.- Diameter of the central capsule 01 to 012, length of the spicula 0'04 to 0'08. 



Habitat. Central Pacific, Station 272, surface. 



Thalassosphcera rhaphidium, n. sp. 



Spicula thick cylindrical rods, more or less curved, pointed at both ends, covered with numerous 

 strong conical thorns, perpendicular to the axis. Central capsule spherical, four times as broad as 

 the central nucleus, with twenty to thirty large oil-globules on the inside of the membrane. 



Dimensions. Diameter of the central capsule 0'2, length of the spicula 012 to 016. 



Habitat. Tropical Atlantic, Station 347, surface. 



Genus 8. Thalassoxanthium? Haeckel, 1881, Prodromus, p. 470. 



Definition. Thalassosphserida without alveoles, with numerous branched or compound 

 spicula in the calymma. 



The genus Tlialassoxanthium differs from the foregoing Thalassosphcera, by the 

 ramification of the spicula, and has therefore the same relation to it as Sphcerozoum to 

 Belonozoum. The soft unicellular body is as simple as in Actissa, and exhibits alveoles 

 neither in the capsule nor in the calymma. 



Subgenus 1. Tlialassoxanthella, Haeckel. 



Definition. Spicula not geminate, but simply radiate, consisting of three, four, or 

 more needles or shanks, radiating in different directions from one and the same point ; 

 shanks now simple or needle-like, now furcate or branched. 



1 Atlantic, vol. i. p. 233, fig. 51, 1877. 2 Thalassoxanthium = Sea-burdock ; Havana,, gdufaoy. 



