REPORT ON THE RADIOLARIA. 259 



= 1:3:9. On the surface about twenty three-sided pyramidal main spines, as long as the radius, 

 and numerous (forty to sixty) by-spines of lialf the length. (Compare with this species Actinomma 

 trinacrium, with which it is connected by transitional forms.) 



Dimensions. — Diameter of the outer shell 0'09, middle 0-03, inner 0-01 ; cortical pores 0-008 to 

 0-012, bars 0-004; length of the spines 0-02 to 0-05, basal breadth 0-01. 



Habitat. — Mediterranean (Messina). 



7. Echinomma toxopneustes, u. sp. (PI. 29, fig. 1). 



Cortical shell thin walled, with large, irregular, roundish, polygonally framed pores, twice 

 to four times as broad as the crested bars. Both medullary shells of similar structure. Eadial 

 proportion of the three spheres = 1:2-5:6. Numerous (thirty to fifty or more) thin radial beams 

 connecting them, prolonged outside into strong three-sided pyramidal spines, shorter than the 

 radius ; each of tlie three wings with two teeth. Between these, numerous smaller angular 

 by-spines of one-quarter to one-half the length. 



Dimensions. — Diameter of the outer shell 0-12, middle 0-05, inner 0-02 ; cortical pores O'Ol to 

 0-03, bars 0-008 ; length of the main .spines 0-05, basal breadth 0-01. 



Habitat. — South-east Pacific (South of Juan Fernandez), Station 300, surface. 



Genus 103. Pitijomma,^ Haeekel, 1881, Prodromus, p. 453. 



Definition. — A s t r o s p li 83 r i d a with three concentric lattice-shells and mimeroua 

 branched radial spines. 



The genns Pityomma diifers from its ancestral form, Actinomma, in the rami 

 fication of its radial spines, and exhibits therefore the same relation to it that Elatomma, 

 among the Haliommida, bears to Haliomma. 



1. Pityomma scoparium, n. sp. 



Cortical shell thick walled, connected with both concentric medullary shells by twenty 

 thin radial beams, which are prolonged outside into twenty large cylindrical radial spines ; these 

 are somewhat shorter than the shell radius, sunple in the proximal inner half, in-egularly branched 

 in the outer half. All three spheres with regular, cu-cular pores, twice to three times as broad 

 as the bars ; radial proportion = 1:2:6. (Similar to Cladococcus scoparius, PI. 27, fig. 2, and 

 Elatomma scoparium, but differs from both in the double medullary shell) 



Dimensions. — Diameter of the outer shell 0-15, middle 0-05, inner 0-025 ; length of the spines O-L 



Habitat. — Central Pacific, Station 273, surface. 



' Pii2/omnia = Pine-eye ; ■jcnv;, ofiy.a. 



