298 



Rossella lychnophora n. sp. 



The single specimen of this species is an oval sack 16 mm long 

 and 11 mm broad. Rather thick diactine prostalia pleuralia project 

 mostly in an upward and downward direction. A fairly continuous ve- 

 lum projects about 3 mm beyond the surface. 



The parenchymal diactins have rounded ends. 



The autodermalia (pentactin and stauractin) have a granular sur- 

 face. The chief distinguishing character of the species is in the calyco- 

 comes. These spicules are very slender at the point of junction of the 

 six main rays, so much so that the field in bestrewn with broken-off rays, 

 the main rays and capitula having the shape of long beaked opercula 

 of moss capsules. The central point of meeting of the axial canals is 

 not a point but a spherical space, when the rays emanate (hence the 

 specific name lychnophora). 



The calycocomes, 247 /t in diameter, have slender main rays tapering 

 to the centre, 9,75 n long, 1,5 u thick at the central end, and 3,75 /< 

 thick at the distal end where they join the capitula. The long slender 

 capitulum in 16 ^< long and 5 ^< broad; the end-rays are 88 u long, and 

 diameter of the distal end of the tuft of end-rays only 19,5 n. The rays 

 vary in number from 2 — 7 but then are commonly 6. Sometimes the 

 capitula are broader and the end-rays more divergent. This species is 

 one of the ,^racovit:,ae'''- group. 



Locality. The unique specimen came from Gauss »Station. 27. IX. 

 1902. 385 m. 



Rossella fibulata n. sp. 



The new species is represented only by three small fragments. The 

 characteristic feature consists in the presence of heterostauractins, 

 heterotriactins and heterodiactins (F. E. Sch.) seu monostaurasters, 

 monotriasters and monodiasters (Kirkp.). The last kind are present in 

 abundance and enable the species to be immediately recognised. 



The typical form of heterodiactins seu monodiasters is a slender 

 sharp pointed rod with four central tubercles; the smaller kind are 

 about 160—200« in length and 7—8« in thickness, the larger kind 

 attain a size of 600 a in length and 26 n in thickness. The largest forms 

 closely resemble the hvpodermal and hypogastral diactine accessoria, but 

 the important point about the heterodiactins (F. E. Sch.) seu monodiasters 

 (Kirkp.) is the abrupt termination of the axial canals a little beyond the 

 centre of the spicule. The large heterodiactins F. E. Sch.) seu mono- 

 diasters (Kirkp.) and the small hypodermal diactins though alike exter- 

 nally have had a very different history; the former are derived from 

 hexasters and the latter from hexactins. This constitutes are interesting 

 cases of convergence. 



