366 THE VOYAGE OF H.M.S. CHALLENGER. 



11. CijpJioniuvi ceratospyris, Haeckel. 



Didymocyrtis ceratosjvjri.-i, Ilaeckel, 1862, Slonogr. d. Radiol, p. 44.5, pi. xxii. figs. 14-16. 

 Haliomma didymocyrtis, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. "VViss. Berlin, p. 816. 



Cortical shell thin walled, with spiny surface ; pores irreguliu', roundish, three to nine times 

 as broad as the bars ; five to six on the half meridian of each chamber, eight to nine on its 

 half equator. Spines of the surface partly very short, partly as long as the largest pores, either 

 radially or obliquely inserted. Medullary shells both spherical. (Ccjnipare the detailed description 

 and figures also of the soft body in my Monograph, he. cii.) 



Dimensions. — Main axis of the cortical shell 012, equatorial axis (in the stricture) 0"06 ; 

 greatest breadth 0-08 ; pores 0-03 to 0-2, bars 0-002 to 0-006, spines 0-05 to 0-015. 



Habitat. — Mediterranean (Messina), Canary Islands (Lanzevote), Haeckel. 



Genus 157. Cypassis,^ n. gen. 



Definition. — C y p h i n i d a with double cortical sliell and double medullary shell, 

 without polar spines or tubes. 



The genus Cypassis differs from Cyphonium l>y duplication of the cortical twin-shell; 

 from the outer surface of the simple twin-shell arise numerous radial spines, which become 

 connected by anastomosing transverse branches, and in this manner form an outer 

 envelope or mantle. Cypassis may alsct be regarded as a Cromyodruppa, the double 

 cortical shell of which is constricted in the equatorial plane. 



Subgenus 1. Didymospyris, Haeckel (1881). 

 Definition. — Surface of the sheU smooth, without thorns or spines. 



1. Cypassis j)CiUiata, n. sp. 



Inner cortical shell thin walled, with regular, circular, hexagonally-franied pores, twice as broad 

 ■as the bars ; seven to eight on the half meridian of each chamber, ten to twelve on its half equatoi-. 

 Outer cortical shell very thin, with smooth surface, and very small, irregular, roundish pores, twice 

 to five times smaller than those of the inner shell. Distance between the two cortical shells 

 equals the diameter of the outer medullary shell, wdiich, like the inner, is spherical. (The net- 

 work of this species resemljles that of Pcripanarius ampliiconiscus, I'l. 40, fig. 5.) 



Dimensions. — Main axis of the external cortical shell 018, of the internal 0-12; greatest 

 breadth (in the equator of each chamber) of the former 0-1:3, of the latter 0-09 ; pores of the outer 

 0-002 to 0-005, of the inner shell 0-01, bars 0-002 to 0005. 



Habitat. — South Pacific, Station 288, surface. 



' Cypassis = KvaoKiaii ; A girl's girdle. 



