REPORT ON THE RADIOLARIA. 747 



3. Zijgacantha compressa, Haeckel. 



Acanf/wnictra conqiressa, Haeckel, 1862, Monogr. d. Radiol., p. 378, Taf. xviii. figs, ia, ih. 



Spines in the proximal half compres.sed, broad lanceolate, four t(i six times as broad as in the 

 thin cylindrical distal half. Apex simple or short bifid. Base pyramidal, thickened, without leaf- 

 cross. No middle rib. Central cajDsule opaque, yellowish or reddish-brown. 



Dimensions. — Length of the spines 0'3 to 0'5, breadth of the inner half 0'015 to 0-02, of the 

 outer half 0-002 to OOO.'l 



Hahifat. — Mediterranean (Messina) ; Atlantic (Canary Islands), Station 352, surface. 



4. Zygacanthd furcata, J. Miiller. 



Zygacaidlia fanata, J. Miiller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 51, Taf. ix. 



fig. 6. 

 Acant/wmctra furcata, J. i^Iuller, 1856, Moiiatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 499. 

 Acanthometra fmrata, Haeckel, 1862, Monogr. d. Radiol., ]>. 380. 



Spines compressed, fork-shaped, divided by two thickened knots into three sections of nearly 

 equal length ; middle section broader than the proximal, but smaller than the distal section, which 

 is cleft by a deep fissure into two long parallel straight branches. Base pyramidal, without leaf- 

 cross. Central capsule purple, with yellow bodies. 



Dimensions. — Length of the spines 01 to 0'15, basal breadth 0'003 to 0-005, distal breadth 

 0-02 to 0-03. 



Habitat. — Mediterranean (Cette), J. Miiller, surface. 



Subgenus 2. Zygacanthidium, Haeckel. 



Definition. — Sjjiues at the central base witli a cross of four prominent leaves ; the 

 meeting edges of the ueighliouring lamellae so rest one upon another that twenty -two 

 hollow pyramidal compartments are formed (compare p. 721). 



5. Zi/gacantha dichotoma, Haeckel. 



Zygacantlia dichotoma, Haeckel, 1862, Monogr. d. Radiol, p. 381. 



Acanthometra dichotoma, J. Mijller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 50, Taf. ix. 

 fig. 5. 



Spines compressed, pincer-shaped, cleft nearly throughout their whole length into two thin parallel 

 straight rods or fork branches, which are united only in their middle by a narrow bridge, and at 

 their central base by the pyramidal smaU central apex ; abo\'e this pyramid each rod is divided 

 into two broad triangular leaves, for-ming a large basal leaf-cross. Central capsule purple, with 

 yeUow bodies. 



Dimensions. — Length of the spines O'l to 0'15, breadth O'Ol to 0'02. 



Habitat. — Mediterranean (Nice), J. MiiUer, surface. 



