870 THE VOYAGE OF H.M.S. CHALLENGEE. 



edged spines ; two primary aspinal pores on the two edges of the latter. Each circular pore is 

 surrounded by a square frame. Spines sword-like, strongly compressed, their outer part longer 

 than the inner. 



Bhnensions. — Length of the shell 0"2 to 0'22, breadth O'lG to 0'18 ; basal breadth of the 

 spines 001. 



Habitat. — North Pacific, Station 254, surface. 



6. Phatnasjns coscinoides, n. sp. 



Parmal pores circular, regular, all of nearly equal size, twelve to sixteen on each side of the 

 primary diagonal rib, which arises from both flat sides of the two-edged spines ; two primary pores 

 on the two edges of the latter. Spines linear, little compressed, their outer part much longer than 

 the inner. 



Dimensions. — Length of the shell O'lS, breadth 0"15 ; breadth of the spines 0'006. 



Habitat. — South Atlantic, Station 325, surface. 



Subgenus 2. Phatnasplenium, Haeckel. 



Definition. — In the centre of each rhomboidal plate two primary aspiual pores, 

 opposite -on the two flat sides of the compressed spines, from the two edges of which 

 the primary diagonal crest arises. 



7. Phatnaspis orthopora, n. sp. 



Parmal pores irregular quadrangular, of unequal size and form, four to six on each side of the 

 primary diagonal rib, which arises from both edges of the compressed spines ; two larger primary 

 aspinal pores opposite on the two flat sides of the latter. Spines very thin and long, linear, their 

 outer half three to four times as long as the inner. 



Dimensions. — Length of the shell 0'08, breadth 0"06 ; breadth of the spines O^OOS. 



Habitat. — North Atlantic, Station 353, surface. 



8. Phatnaspis polypora, n. sp. 



Parmal pores irregular polygonal, of very unequal size and form, sixteen to twenty on each side 

 of the primary diagonal rib, which arises from both edges of the compressed spines ; two very large, 

 lanceolate, primary aspinal pores opposite on the two flat sides of the latter. Spines very thin, 

 linear, on the outside of the shell rudimentary. (This remarkable species somewhat resembles 

 Coscinaspis polypora, PI. 136, fig. 8.) 



Dimensions. — Length of the shell 0-32, breadth 0-24 ; breadth of the spines 0-002. 



Habitat. — South Atlantic, Station 332, surface. 



