EEPOET ON THE RADIOL AEIA. 771 



broad as the sixteen smaller spines, which are cylindrical, of equal breadth throughout theh 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 O'OCG, Ijreadth in the middle O'OOo, on the apex 

 0"008 ; length of the sixteen smaller spines 0'0o4, breadth O'OOl. 



Habitat. — Mediterranean (Messina), surface. 



Subgenus 2. Staurolithmm, Haeckel, 1862, Monogr. d. Radiol., p. 401. 



Definition. — All twenty sj^ines in the centre melted and grown togetlier, forming 

 ■one single, star-like piece of acanthin. 



8. Acanthostaurus cruciatus, Haeckel. 



Staurolithmm erueiatiim, Haeckel, 1862, Monogr. d. EaJiol., p. 401, Taf. xx. fig. 6. 

 Astrolithium crudatum, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 811. 



Splines cylindrical, of equal breadth throughout their whole length. Apex simple conical. Tour 

 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 capside 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 O'OOo. 



Habitat. — Mediterranean (Messina), surface. 



Genus 335. Belonostaurus,^ n. gen. 



Definition. — Q u adr il on c h id a 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 Acantliostaurus in the unequal 

 size and form of the eight tro2Mcal and the eight polar spines ; the hitter are much 

 smaller tlian 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 scjuare disk. 



1. Belonostaurus quadratus, n. sp. 



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

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



' jBefo(ios(auru«= Needle cross ; ^Aiam, aracvoi;. 



