EEPORT ON THE RADIOLARIA. 801 



4. Porocapsa coronodon, n. sp. 



Perspinal holes circular, with ciliated margin, which forms a crown of sixteen to twenty-four 

 thin parallel teeth. Poruli of the shell surrounded by an elevated ring with high crenated margin. 

 Four edges of the spines denticulate. 



Dimensions. Diameter of the shell 0~55 ; length of the spines 0'15. 



Habitat. Antarctic Ocean, Station 154, surface. 



Genus 347. Cannocapsa^ n. gen. 



I 



Definition. S phserocapsida with twenty radial spines shorter than the radius 

 of the shell ; therefore their distal ends not connected with the twenty perspinal holes, 

 which are prolonged outside into radial tubes (each one in the radial ideal prolongation 

 of one inner spine). 



The genus Cannocapsa exhibits the same peculiar reduction of the radial spines as 

 the foregoing Porocapsa ; the spines are also here shorter than the shell-radius and do 

 not therefore reach the perspinal holes of the shell. But whilst these latter are simple 

 in Porocapsa, they are prolonged into radial tubules in Cannocapsa ; the outer surface 

 bears therefore twenty such cylindrical tubules, separated by a short distance from the 

 inner enclosed spines, but disposed quite regularly according to the law of Icosacantha. 



1. Cannocapsa osculata, n. sp. 



Perspinal holes prolonged into short cylindrical tubuli, the length of which about equals their 

 diameter. Both ends of the tubuli with smooth thickened margin. Poruli of the shell simple, 

 without ring and dimple. Four edges of the spines smooth ; their length equals about four-fifths 

 of the shell-radius. 



Dimensions. Diameter of the shell 0'24 ; length of the spines 0'09, of the tubuli O'Ol. 



Habitat. North Atlantic, Fseroe Channel (Gulf Stream), surface, John Murray. 



2. Cannocapsa stethoscopium, n. sp. (PI. 133, fig. 8). 



Perspinal holes prolonged into cylindrical tubuli, half as long as the shell radius. Both ends of 

 the tubuli with smooth thin trumpet-shaped margins. Poruli of the shell simple, without ring and 

 dimple. Four edges of the spines smooth ; their length about equals three-fourths of the shell-radius. 



Dimensions. Diameter of the shell 0'2; length of the spines 0'08, of the tubuli 0'05. 



Habitat. South Atlantic (west of Tristan da Cunha), Station 333, surface. 



3. Cannocapsa tubulosa, n. sp. 



Perspinal holes prolonged into cylindrical tubuli, which are as long as or longer than the 

 shell-radius. Both ends of the tubuli with smooth thickened margin. Poruli of the shell simple, 



1 Cannocapsa = Tubular capsule ; xaui/a, KI^. 



(ZOOL. CHALL. EXP. PART XL. 1885.) Rr 101 



