REPORT ON THE RADIOLARIA. 315 



Dimensions. Major axis 012, minor 0'08 ; pores 0'06 to 0'012, bars - 003 ; main axes of the 

 medullary shells 0'05 and 0'025. 



Habitat. Indian Ocean, between Socotra and Ceylon, surface, Haeckel. 



8. Prunulum fenestratum, Haeckel. 



Adinomma fvnestratum, Stohr, 1880, Palteontogr., vol. xxvi. p. 94, Taf. iii. fig. 2. 



Cortical shell thick walled, rough, with irregular ; roundish pores, once to three times as broad as 

 the bars; twelve to fourteen on the half equator. Proportion of the two axes = 9 : 8. Both medul- 

 lary shells ellipsoidal. (The pores in Stcihr's description are by mistake called "regular"; in the 

 figure they are very irregular, as also in the fossil specimens observed by myself. Between the 

 cortical pores arise very short irregular thorns.) 



Dimensions. Major axis 012 to 015, minor 01 to 012 ; pores 0'003 to O'Ol, bars 0'003; 

 main axis of the outer medullary shell 0'07 to 0'09, of the inner 0'03 to 0'04. 



Habitat. Fossil in the Tertiary rocks of Sicily ; Grotte, Stohr, Caltanisetta, Haeckel. 



9. Prunulum pyrenium, n. sp. 



Cortical shell very thick walled, smooth, with large irregular, roundish pores, three to four times 

 as broad as the bars; six to eight on the half equator. The bottom of each funnel-like pore is closed 

 by a thin siliceous membrane, perforated by three to five irregular roundish pores. Proportion of 

 the two axes = 4: 3. Both medullary shells ellipsoidal. (Closely resembles Stylatractus sethoporvs, 

 I'l. 17, figs. 2, 3, but is devoid of the polar spines.) 



Dimensions. Major axis 016, minor 012; pores Q'015 to 0'02, bars 0~005 ; porules O'Ol; main 

 axes of the medullary shells 0'07 and 0'03. 



Habitat. Western Tropical Pacific, Station 225, depth 4475 fathoms. 



Genus 134. Prunocarpus? n. gen. 



Definition. Druppulida with simple ellipsoidal cortical shell and double 

 medullary shell, with numerous radial spines, but without polar tubes. 



The genus Prunocarpus differs from Prunulum only in the radial spines of the 

 cortical shell, and exhibits therefore the same relation to it that Druppocarpus bears 

 to Druppula. While in the latter the medullary shell is simple, in the former it is 

 double. 



Subgenus 1. Prunocarpetta, Haeckel. 



Definition. Network of the cortical shell regular, with meshes of equal size and 

 similar form. 



1 Prunocarpus Plum fruit ; itinvvov, xa 



