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



3. Stylartus palatus, n. sp. 



Shell thick walled, thorny, with irregular, roundish pores, twice to three times as broad as the 

 bars ; fifteen to eighteen on the half equator of each chamber. On each pole of the main axis a 

 large conical spine, surrounded by a group of ten to fifteen smaller spines, one-third to two-third.s 

 as long as the breadth of the deep equatorial stricture. 



Dimensions. — Length of the shell 0"14, greatest breadth 0'09 ; length of the polar spines 0'03 to 

 0-06, basal breadth 0-005 to 0-015. 



Habitat. — Indian Ocean, Madagascar, Eabbe, surface. 



4. Stylartus penicillus, n. sp. 



Shell thin walled, smooth, with irregular, roundish pores, three to four times as broad as the 

 bars ; ten to twelve on the half equator of each chamber. On each pole of the main axis a brush- 

 like bunch of twenty to thirty thin conical radial spines, half as long as the shell. 



Dimensions. — Length of the shell 0-15, greatest breadth O-l ; length of the polar spines Q-QS, 

 basal breadth 005. 



Habitat — Equatorial Atlantic, Station 3-47, surfaca 



Genus 154. Cannartus,^ Haeckel, 1881, Prodromus, p. 462. 



Definition. — Artiscida -with two hollow polar tubes (fenestrated cylindrical or 

 conical tubuli, opposite on the two poles of the main axis). 



The genus Cannartus differs from Artiscus by the production of two opposite hollow 

 tubes on both poles of the main axis. The cavity of the conical or cylindrical fenes- 

 trated tubes communicates freely with that of the shell ; the network in both is the 

 same. The distal end of the tubes is nearly always broken off, sometimes closed, with a 

 conical apex. Cannartus can be derived either from Pipettella by a transverse equatorial 

 constriction, or from Cannartiscus hj the loss of the medullary shell, or from Artiscus 

 by the production of the polar tulles. 



1. Cannartus violina, n. sp. (PI. 39, fig. 10). 



Pores of the shell subregular, circular, twice to three times as broad as the bars ; eighteen to 

 twenty on the half meridian, fourteen to sixteen on the half equator. Shell-wall in the " tropical 

 zone" of both halves thickened. Polar tubes nearly cylindrical, about as long as the main axis, 

 distal ends broken off. 



Dimensions. — Main axis 0-14, equatorial axis 009 ; meshes 0-008, bars 0-003 ; length of the 

 polar tubes 0-12, breadth 0-02 to 0-03. 



Habitat. — Pacific, central area. Station 268, depth 2900 fathoms. 



1 Cannartus=hoaf with tubes ; xdvuec, afroj. 



