REPORT ON THE RADIOLARIA. 37 



The genus Lampoxanthium differs from the foregoing, Thalassoplancta, by the 

 composite form of the spicula, which are not simple needles, but radiate or gemmate, or 

 branched in different forms ; the former stands therefore in the same relation to the latter 

 as the social Belonozoum to Sphcerozoum. The spicula of some species of Lampoxanthium 

 are identical with those of some species of Sphcerozoum, so that the latter may be derived 

 from the former by forming colonies. The large central capsule is enveloped by a very 

 voluminous alveolated calymma, and includes a large central nucleus with numerous 

 nucleoli. 



Subgenus 1. Lampoxanthella, Haeckel. 

 Definition. Spicula all (or nearly all) of one kind, radiate, 



1. Lampoxanthium tetractinium, n. sp. 



Spicula all (or nearly all) tetraradiate, with four thorny, straight, pointed shanks, radiating from 

 one common point. (Intermingled with these are often some few, thorny, triradiate spicula.) On 

 the inside of the capsule a layer of large oil-globules as in Tlialassoplancta, PL 2, fig. 2. 



Dimensions. Diameter of the central capsule 0'2, of the nucleus 0'08, of the calymma 0'8. 



Habitat. South Pacific, Station 288, surface. 



Subgenus 2. Lampoxanthomma, Haeckel. 



Definition. Spicula all (or nearly all) of one kind, geminate-radiate, with a simple 

 middle rod and two to four diverging shanks on each end of it. 



2. Lampoxanthium punctatum, n. sp. 



Spicula all geminate-triradiate, thorny, of the same form as in the common Sphcerozoum punctatum, 

 of which this species is the large solitary representative. The spicula are aggregated in a very 

 condensed layer on the surface of the large calymma. 



Dimensions. Diameter of the capsule 0'8, of the nucleus 0'6, of the calymma 2 - 0. 



Habitat. North Pacific, Station 248, surface. 



3. Lampoxanthium octoceras, n. sp. 



Spicula all geminate-quadriradiate, with a very short simple middle rod and four very long 

 divergent shanks on both ends of it ; the shanks are smooth, five to ten times as long as the middle 



