REPOET ON THE RADIOLARIA. 657 



2. Amphipylonium spinosissimum, u. sp. 



Inner cortical shell lentelliptical, one and a third times as long as broad, with thorny surface and 

 four kidney-shaped gates. Transverse girdle of the outer cortical shell very spiny, with two semi- 

 lunar wings, with convex thorny lateral crests; each wing one and a half times as broad as 

 the transverse girdle of the inner cortical shell, and one and a half times as long as its lateral 

 girdle. 



Dimensions. — Length of the lentelHptical medullary shell O'Oo, breadth 0"03 ; length of the 

 inner cortical shell 0'016, breadth 012 ; length ' of each lateral wing of the outer cortical shell 

 0-24, breadth 018. 



Habitat. — Western Tropical Pacific, Station 225, depth 4475 fathoms. 



3. Ampliipylomum tetraceros, n. sji. 



Inner cortical shell hexagonal, one and a half times as long as broad, with smooth surface and 

 four transverse elliptical gates. Transverse girdle of the outer cortical shell smooth, with rectilinear 

 smooth lateral crests, which are prolonged at both ends into strong conical spines (therefore four 

 spines in the lateral plane); each wing of the same breadth as the transverse girdle of the inner 

 cortical shell, and twice as long as its lateral girdle. 



Dimensions. — Length of the hexagonal medullary shell 0"03, breath 0'02 ; length of the inner 

 cortical shell 012, breadth O^OS ; length of each lateral wing of the outer cortical shell 0'24, 

 breadth 008. 



Habitat. — Northern Pacific, Station 253, depth 3125 fathoms. 



4. Amp>hi2)ylonium octoceros, n. sp. 



Inner cortical shell quadrangular, one and a third times as long as broad, with thorny surface and 

 four kidney-shaped gates. Transverse girdle of the outer cortical shell thorny, constricted at tiie 

 equator, with concave thorny lateral crests, and with eight strong radial spines, opposite in pau-s 

 and lying in two crossed diagonal planes; each wing narrower than the transverse girdle of the 

 inner cortical shell and twice as long as its lateral girdle. 



Dimensions. — Length of the subspherical medullary shell 0'04, breadth 0'035 ; length of the 

 inner cortical shell 014, breadth Oil ; length of each lateral wing of the outer cortical shell 0'26, 

 breadth 009. 



Habitat. — Southern Pacific, Station 295, depth 1500 fathoms. 



Genus 287. Tetrapylonium^ Haeckel, 1881, Prodromus, p. 464. 



Definition. — P y 1 o n i d a with trizonal lentelliptical medullary shell, surrounded 

 by a double latticed cortical shell ; inner cortical shell P?//o/iM<m-shaped, with three 

 perfect crossed girdles ; outer cortical shell represented by two crossed girdles, one 

 (smaller) transverse and one (larger) lateral girdle. 



' r«<ra;)?/Zo'/ii?M)i= Building with four gates ; -rtr^a, izv'hu'jtai/. 

 (ZOOL. CHALL. EXP. — r.4.RT XL. — 1885.) Er 83 



