REPORT ON THE RADIOLARIA. 823 



with two large aspinal pores), and fifty to one hundred and fifty or more smaller dimples (each with 

 one small sutural pore). No blind dimples. Crests between the dimples armed with forked 

 by-spines. Eadial main spines stout, leaf-shaped, tapering towards both ends. 



Dimensions. Diameter of the shell - 12, parmal pores O'Ol, sutural pores O'OOS. 



Habitat. Central Pacific, Station 276, surface. 



3. Hystrichaspis cristata, n. sp. (PI. 138, fig. 11). 

 Siplionasphis cristata, Haeckel, 1882, Manuscript. 



Shell with numerous (one hundred to two hundred ?) funnel-shaped dimples, each of which is 

 pierced at the bottom by one or more pores. Twenty larger dimples in the centre of the plates are 

 pierced by the radial main-spines ; among these fourteen contain each a couple of aspinal pores ; six 

 others are much larger, and contain each six larger pores ; these six plates are two opposite 

 equatorial plates and four polar plates, placed in the same meridian plane (the " hydrotomical 

 plane ") ; in each of these six " hydrotomical dimples " two pores are placed opposite to one another 

 on the two edges of the leaf-shaped spine, four others being opposite in pairs on both flat sides of 

 it. By this peculiar structure this species connects the true Hystrichaspis with Hexalaspis and 

 Diploconus ; however the twenty spines are of equal length, and the shell continues to be spherical. 

 The twenty radial main-spines are leaf-like and compressed. The crests between the dimples are 

 dentated by a series of small by-spines. 



Dimensions. Diameter of the shell - 15, of the aspinal pores O'Ol, of the sutural pores O'OOo. 



Habitat. North Pacific, Station 240, surface. 



Subgenus 2. Hystrichaspidium, Haeckel. 



Definition Shell-surface with numerous funnel-shaped dimples (commonly one 

 hundred and seventy-six to one hundred and eighty-two), which on the bottom are 

 partly closed, partly perforated by one aperture (or by a pair of pores). The blind 

 dimples are situated on the corners of the twenty plates ; their number is commonly 

 one hundred and four or one hundred and eight, sometimes more. The perforated 

 dimples, alternating with the former, are usually seventy-two to seventy-four, some- 

 times more ; twenty larger parmal dimples (each with a couple of aspinal pores, 

 sometimes also with three such couples) and fifty-two to fifty-four sutural dimples, 

 sometimes one hundred or more (each with one sutural pore). (Compare the definition 

 of Ceriaspidium, p. 820.) 



4. Hystrichaspis dorsata, n. sp. (PI. 138, fig. 10). 



Shell with one hundred and seventy-six funnel-shaped dimples, one hundred and four of which 

 are blind and seventy-two perforated ; of the latter, each of the fifty-two smaller contains a single 



