REPORT ON THE RADIOLARIA. 771 



broad as the sixteen smaller spines, which are cylindrical, of equal breadth throughout their whole 

 length, with bifid apex. Base of all twenty spines pyramidal, without leaf-cross. Central capsule 

 yellow, spherical, or lenticular. 



Dimensions. Length of the four major spines O066, breadth in the middle O005, on the apex 

 O'OOS ; length of the sixteen smaller spines 0'054, breadth O'OOl. 



Habitat. Mediterranean (Messina), surface. 



Subgenus 2. Staurolithium, Haeckel, 1862, Monogr. d. Eadiol., p. 401. 



Definition. All twenty spines in the centre melted and grown together, 'forming 

 one single, star-like piece of acanthin. 



8. Acanthostaurus cruciatus, Haeckel. 



Staurolitltium erueiatum, Haeckel, 1862, Monogr. d. Eadiol., p. 401, Taf. xx. fig. 6. 

 AstroHthium erueiatum, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 811. 



Spines cylindrical, of equal breadth throughout their whole length. Apex simple conical. Four 

 equatorial spines twice as long and broad as the sixteen other spines. All twenty spines in the 

 centre melted and grown together, forming a single piece of acanthin. Central capsule spherical, 

 red-brown, opaque. 



Dimensions. Length of the four equatorial spines 0'12, breadth O'OOG ; length of the sixteen 

 smaller spines 0'06, breadth 0'003. 



Habitat. Mediterranean (Messina), surface. 



Genus 335. Belonostaurus, 1 n. gen. 



Definition. Q uadrilonchida with four equatorial spines of equal size and 

 form, which are much larger than the sixteen other spines. Eight tropical and eight 

 polar spines very different. No apophyses. 



The genus Belonostaurus differs from the preceding Acanthostaurus in the unequal 

 size and form of the eight tropical and the eight polar spines ; the latter are much 

 smaller than the former and often quite rudimentary, so that the skeleton appears 

 composed only of twelve spines, four larger equatorial and eight smaller tropical spines. 

 The central bases of the polar spines are constantly preserved. The central capsule 

 is a flattened square disk. 



1. Belonostaurus quadratus, n. sp. 



Four equatorial spines little compressed, almost cylindrical in the basal half, lanceolate, broader, 

 with simple apex in the distal half. Eight tropical spines a little shorter, but only half as broad, 



1 Belonostaurus = Needle cross ; j3-7m'v>), orai/no';. 



