REPORT ON THE RADIOLARIA. 303 



Dimensions. Longer axis of* the shell 012, shorter axis 0'09; pores and bars OD04 to 0'006 ; 

 length of the polar spines longer 012, shorter - 06. 

 Habitat. FoasR in Barhados. 



4. Lithomespilus flammdbundus, n. sp. (PL 14, fig. 14). 



Proportion of the major axis to the minor = 4: 3. Shell thin walled, with irregular, roundish 

 pores, partly simple, partly composed of three to six confluent pores ; only six to eight pores on 

 the half equator, twice to four times as broad as the bars. Surface spiny. Length of the conical 

 irregular spines increasing towards the poles ; each polar spine surrounded by a flame-shaped, 

 circumpolar area of longer spines ; all large spines (also the polar spines) curved or contorted at 

 one pole and much stronger and more numerous than at the other ; length variable, often equal to 

 the longer axis. 



Diiiu'nsions. Longer axis of the shell 0'12, shorter axis 0'09 ; pores O'OOS to 0'015, bars 0'003 to 

 0'005 ; length of the polar spines 01 to 015. 



Habitat. Western part of the Tropical Atlantic, Station 347, depth 2250 fathoms. 



Genus 129. Lithapium, 1 n. gen. 



Definition. Ellipsida with simple ellipsoidal or pear-shaped shell; with a 

 single spine only situated at one pole of the main axis. 



The genus Lithapium represents a peculiar modification of Ellipsoxiphus ; one of 

 the two opposite polar spines disappears by reduction, and in this way only a single spine 

 remains, at one pole of the main axis. For this reason the shell assumes a characteristic 

 pear-shape, and may easily be confounded with some similar Monocyrtida (Halicapsa). 



1. Lithapium pyriforme, n. sp. (PI. 14, fig. 9). 



Proportion of the longer axis to the shorter = 6:5. Shell thin walled, with regular, circular 

 pores, four times as broad as the bars ; six to eight on the half equator. Surface a little thorny. 

 The single polar spines three-sided pyramidal, as broad at the base as one mesh, about as long as 

 the radius of the shell. (In the specimen figured, there was on the opposite pole a little rudiment 

 of the other lost polar spine ; it is missing in other specimens.) 



Dimensions. Major axis of the ellipsoidal shell 012, minor axis 01 ; pores 0'02, bars 0'005 ; 

 length of the single polar spine 0'05, basal thickness 0'02. 



Habitat. Central area of the Pacific, Station 266, depth 2750 fathoms. 



k 



2. Lithapium halicapsa, n. sp. (PI. 14, fig. 8). 



Proportion of the longer axis to the shorter = 6:5. Shell thin walled, with irregular, lobed 

 meshes, six to eight on the half equator, twice to five times as broad as the bars ; each mesh 



1 Lithapium = Siliceous pear ; x/0o?, &KIOI/. 



