REPORT ON THE RADIOLARIA. 769 



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Subgenus 1. Acostaurus, Haecke). 



Definition. — All twenty spines separated, in the centre united only by the triangular 

 faces or the meeting leaf-shaped edges of their pyramidal bases. 



1. Acanthostaurus aequatorialis, n. sp. 



Spines cylindrical, of nearly equal breadth throughout their whole length. Apex simple conical. 

 Base with a large leaf-cross. Four equatorial spines of the same form as the sixteen others, but 

 much longer and about three times as broad. 



Dimensions. — Length of the four major spines 0'2 to 0'25, breadth O'OOS ; length of the sixteen 

 minor spines O'Ol to 0'15, breadth 0'003. 



Habitat. — Equatorial Pacific, Station 271, surface. 



2. AcantJiostaurus hipennis, n. sp. 



Spines linear, sword-shaped, strongly compressed, two edged ; of nearly equal breadth in their 

 whole length. Apex bifid. Base with a small leaf-cross. Four equatorial spines of the same form 

 as the sixteen others, but twice as long and as broad. 



Dimensions. — Length of the four major spines 04 to 0'5, of the sixteen minor 0"2 to 0'3 ; 

 breadth of the former 0-02, of the latter 0-01. 



'Habitat. — North Pacific, Station 244, surface. 



3. Acanthostaurus conacantlius, n. sp. 



Spines conical, short, gradually tapering from the thick base towards the simple apex. Base 

 with large leaf-cross. Four equatorial spines more cylindrical, twice to three times as long and as 

 broad as the sixteen others. 



Dimensions. — Length of the four major spines 0'15 to 0'2, of the sixteen minor 0'0.5 to 0'08 ; 

 basal breadth of the former 0'03, of the latter 0'012. 



Habitat. — South Atlantic, Station 332, surface. 



4. Acanthostaurus lyurpurascens, Haeckel. 



Aeantfiostaurus 2>urpuraseens, Haeckel, 1862, Monogr. d. Radiol., p. 395, Taf. xix. figs. 1, 2. 

 Acant/iostaurus jmrpurascens, R. Hertwig, 1879, Organism, d. Radiol., Taf. i. figs. 8, 9, Taf. iii. 



figs. 13, 15. 

 Acanthometra imrpurascens, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 



p. 809. 



Spines nearly cylindrical, with four blunt (often scarcely visible) edges, tapering slightly from the 

 central to the distal end. Apex bifid, with two short parallel teeth. Base with a Inroad leaf-cross. 



(ZOOL. CHALL. EXP. PART XL. — 188.5.) Rp 97 



