REPORT ON THE RADIOLARIA. 1291 



long as broad, with slightly convex outlines ; its pores subregular, circular, half as broad as the 

 cephalis. 



Dimensions. Cephalis 0'03 long, 0'02 broad ; thorax 015 long, 014 broad. 



Habitat. Fossil in Barbados. 



3. Sethoconus pileus, n. sp. 



Cephalis subspherical, free, with distinct collar stricture, a conical oblique horn of the same 

 length, and small, irregular, roundish pores. Thorax flatly conical, about half as long as broad, with 

 straight outlines ; its pores subregular, hexagonal, half as broad as the cephalis, with very thin 

 bars. 



Dimensions. Cephalis 0'02 long, 0'02 broad ; thorax 0'08 long, 016 broad. 



Habitat. Central Pacific, Stations 262 to 274, surface. 



4. Sethoconus ampliatus, Haeckel. 



Cornutella ampliata, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. ii. fig. 5. 

 Ceratocyrtis ampliata, Biitschli, 1882, Zeitschr. f. wiss. Zool., Bd. xxxvi. p. 536. 



Cephalis, hemispherical, thorny, with a conical horn of twice the length; it is separated from 

 the thorax by a complete internal collar septum, but without external collar stricture. Thorax 

 flatly conical, about half as long as broad, with straight outlines ; its pores subregular, hexagonal, 

 about as large as the cephalis, with thin bars. 



Dimensions. Cephalis 0'015 long, 0'03 broad ; thorax 0'08 long, 018 broad. 



Habitat. Fossil in Barbados. 



5. Sethocdnus mitra, Haeckel. 



Cornutella mitra, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. ii. fig. 8. 

 Ceratocyrtis mitra, Biitschli, 1882, Zeitschr. f. wiss. Zool., Bd. xxxvi. p. 536. 



Cephalis ovate, with slight collar stricture (not distinct enough in Ehrenberg's figure), with 

 few large pores, and a conical stout horn of the same length. Thorax campanulate, conical, twice as 

 long as broad, with slightly convex outlines ; its pores subregular, roundish, increasing in size 

 towards the mouth, the largest as broad as the cephalis. 



Dimensions. Cephalis, 0'03 long, 0'02 broad ; thorax 012 long, 0'07 broad. 



Habitat. Tropical Atlantic, Station 347, depth 2250 fathoms ; fossil in Barbados. 



6. Sethoconus rayianus, n. sp. (PI. 58, fig. 6) 



Conarachnium rayianum, Haeckel, 1881, Prodromus, p. 430. 



Cephalis ovate, with obliterated collar stricture (but distinct internal septum), with small, 

 irregular pores, and two to four divergent horns, which are longer than the cephalis, and two or 

 three of which are forked. Thorax tent-shaped, conical, two-thirds as long as broad, with slightly 



