REPORT ON THE RADIOLARIA. 1053 



20. Challengeria ivildi, n, sp. (PL 99, fig. 2). 



Shell subspherical, slightly compressed. Peristome semitubular, curved, as long as the shell- 

 radius ; with five curved lamellar teeth, an odd longer dorsal tooth and two pairs of lateral teeth. 

 Dimensions. Diameter of the shell 012 to 018, length of the peristome 0'08 to 012. 

 Habitat. Tropical Atlantic, Stations 347 to 348, depth 2250 to 2450 fathoms. 



21. Challengeria aldrichi, John Murray. 



Challengeria aldrichi, John Murray, 1879, in litteris, Narr. Chall. Exp., vol. i. p. 226, pi. A, fig. 4. 



Shell subspherical, slightly compressed. Peristome a collar-like curved lamella, the breadth of 

 which is twice as great as its length, and equals the radius of the shell ; its margin with six short 

 triangular teeth, two convergent ventral, two external horizontal lateral, and two ascending dorsal. 



Dimensions. Diameter of the shell 0'2, breadth of the peristome 01. 



Habitat. North Pacific, Station 244 to 248, depth 2050 to 2900 fathoms. 



22. Challengeria murrayi, n. sp. (PI. 99, fig. 1). 



Shell subcircular, lenticular, strongly compressed. Peristome a trapezoidal, curved, collar-like 

 lamella, the breadth of which is three times as great as its length and equal to the diameter of the 

 shell ; its margin with six triangular teeth, disposed like the preceding species, but larger. 



Dimensions. Diameter of the shell 015, breadth of the peristome 015. 



Habitat. North- Western Pacific (south of Japan), Station 231, depth 2250 fathoms. 



Genus 695. Challengeron, John Murray, 1879, in litteris et schedulis. 



Definition. C hallengerida without pharynx, with one or more teeth on the 

 mouth, and with marginal spines. 



The genus Challengeron has in general the same shape as the preceding closely 

 allied Challengeria, but differs from it in the development of radial spines on the 

 sagittal margin of the shell, which in the latter genus is smooth. According to the 

 different number and arrangement of these marginal spines, which give a very singular 

 appearance to them, we divide the twenty -five species of this cosmopolitan genus into 

 four subgenera : (l) with a single, odd apical spine ; (2) with two opposed aboral spines 

 (a dorsal and a ventral) ; (3) with a bunch of aboral spines ; (4) with numerous radial 

 spines along the whole sagittal margin of the shell. 



Subgenus 1. Challenger anium, Haeckel. 



Definition. Margin of the shell with a single spine on the apical pole, opposite to 

 the peristome (Challengerice caudatce). 



