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



Subgenus 2. Peripanartium, Haeckel. 

 Definition. — Surface of the outer cortical shell covered with spines or tlioriis. 



4. Peripanartus atractu.'^, u. sp. (Pi. 40, fig. 7). 



Inner cortical shell with four very unequal chambers; both proximal cliumbers spheroidal (with 

 subregular, roundish pores, twice to three times as broad as the bars), both distal cliambers nearl}' 

 conical, with a circle of eight to ten very large stpiare pores at the base ; the other pores very 

 small, roundish. Outer cortical shell envelops only the proximal cliambers and tlie l)asal half 

 of the distal chambers, appearing as the direct continuation of the microporous covering of 

 their apical half. The whole external cortical shell is inflated in the ecpiatorial zone, and hence 

 assumes an irregular, spindle-like appearance. Its whole surface is rough with innumerable very 

 short thorns. 



Dimensions. — Main axis 0'28, equatorial axis 0"l7 ; pores of the external cortical shell 0"002 to 

 0-004, bars 0'002 ; main axis of the proximal chambers of the internal cortical shell 0'07, equatorial 

 axis 0-09 ; pores 0-007, bars 0004. 



Habitat. — North Pacific, Station 244, dejitli 2900 fathoms. 



5. Peripanartvs ci/Iin<Jriis, n. sp. (PI. 40, fig. G). 



Internal cortical shell with four unequal chambers ; both proximal chambers kidney-shaped (with 

 regular, circular, hexagonally framed pores of the same breadth as the bars), both distal chambers 

 nearly hemispherical, with a circle of eight to ten very large square pores at their base ; the other 

 pores very small, roundi.sh. External cortical sliell envelops tlie whole internal like a perfect 

 hollow cylinder, whicli is closed at Ijoth poles l)y a hemispherical cap. The whole surface 

 of this cylindrical mantle is perforated Ijy innumeraljlc very small roundish jiores, and covered 

 with small bristle-like spines. 



Bwiensions. — Main axis of the eylinder O'o, equatorial axis 012 ; pores and bars 0'006 ; 

 spines of its surface 0-012 to 0"15 ; main axis of the internal cortical shell 0'2 ; equatorial axis (in 

 the constriction) O'OG ; pores and bars of its proximal chambers 0-007, of its distal chambers 0-003 ; 

 large square pores at their base 0-02. 



Hahitai. — Pacific, central area. Stations 270 to 274 , depth 2050 to 292.5 fathoms. 



Gemis 165. Paniciuni,^ n. gen. 



JJefinitiou. — Puuurtida with simple cortical shell and double medullar)- shell, 

 w^ith two opposite apical spines ou both poles of the main axis, or with a group of polar 

 spines. 



The genus Panicitim comprises those forms of Panartus which develop a peculiar 

 armature on both poles of the cortical shell. This may be only a single strong spine 



' Panicium = A. kind of brearl. 



