REPORT ON THE RADIOLARIA. 779 



Therefore the wings or lattice-plates have quadrangular meshes and lie in one 

 meridian plane of the spine, not in a tangential plane (as in the Acanthophracta). 

 Commonly the lateral ends of the four .broad equatorial wings, are so crossed that one 

 lateral corner of each wing lies on the upper, the other corner on the under side of both 

 its neighbours ; but sometimes the meeting corners have grown together. 



Subgenus 1. Lithopteranna, Haeckel. 



Definition. Four equatorial spines with transverse apophyses ; sixteen others 

 (eight tropical and eight polar spines) simple, without apophyses. 



1. Lithoptera tetraptera, n. sp. (PI. 131, fig. 9). 



Four equatorial spines spindle-shaped, with latticed apophyses, each crossed by two transverse 

 beams which are connected at equal distances by four rods parallel to the spine (therefore each wing 

 with four square meshes in a single row). Lateral corners of the neighbouring wings not 

 meeting. Sixteen smaller spines (eight tropical and eight polar) simple, conical, without apophyses. 



Dimensions. Diagonal of the square body 0'24; length of the inner square 0'16. 



Habitat. Tropical Atlantic, Station 348, surface. 



2. Lithoptera miilleri, Haeckel. 



Lithoptera miilleri, Haeckel, 1862, Monogr. d. Radio!., p. 398, Taf. xx. figs. 1, 2. 



Four equatorial spines four-edged, with large latticed apophyses, each crossed by three 

 transverse beams, which are connected at irregular distances by eight to twelve rods parallel to the 

 spine (therefore each wing with two rows of rectangular meshes). The wings are placed not 

 perfectly in the equatorial plane, but a little obliquely, so that each wing lies with one lateral corner 

 on the upper, with the other corner on the under side of its neighbours. Sixteen smaller spines 

 simple, thin, cylindrical, without apophyses. 



Dimensions. Diagonal of the square body 0'3 ; length of the inner square 017. 



Habitat. Mediterranean (Messina), surface. 



3. Lithoptera lamarckii, n. sp. 



Four equatorial spines four-edged, with large latticed apophyses ; each crossed by three trans- 

 verse beams, which are connected at short distances by twelve to sixteen rods parallel to the spine 

 (therefore each wing with two rows of hexagonal or nearly elliptical meshes). Wings placed as in 

 Lithoptera mulleri. Sixteen smaller spines simple, thin, prismatic, without apophyses. 



Dimensions. Diagonal of the square body 0'35 ; length of tb>- inner square 0'2. 



Habitat. Central Pacific, Station 271, surface. 



