48 DE. G. J. HINDE ON THE EADIOLAETA IN THE [Feb. 1 899, 



Trilonche vetusta, sp. nov. (PL VIII, fig. 18.) 



The cortical test, as seen in section, is thin, with small lattice- 

 pores and surface-spines ; the inner test has minute circular pores 

 enclosed b}^ a polygonal framework ; the radial spines are moderately 

 stout, keeled or prismatic, subequal in length, and at unequal distances 

 apart : they appear to be in the same plane. The proximal end of 

 the spines is stout, and connects the medullary with the cortic-al 

 sphere. Diameter of outer test, 0-095 mm.; of inner test, 0'045 mm. ; 

 length of spines, 0*09 mm., and thickness at base, 0*025 mm. In 

 volcanic tuff. iS"o. 387 d. 



Trilonche vetusta, var. a. (PI. YIII, fig. 19.) 



This form is very similar to the preceding, but the surface 

 appears to be smooth and the pores of the test somewhat finer. In 

 addition to the three normal spines, which are unequal in length 

 and in their distance apart, there is a small supernumerary radial 

 spine. Diameter of cortical test, 0*1 mm. ; of medullary test, 0*042 

 mm. ; length of spines, 0*06 to 0*09 mm., and thickness at base, 

 0-025 mm. In volcanic tuff. No. 387 d. 



Trilonche Pittmani, sp. nov. (PL YIII, figs. 20 & 21.) 



Cortical test with small pores; medullary test very delicate; 

 pores circular ; radial spines stout, keeled, unequal in length, and 

 at nearly equal distances from each other. Of the two specimens 

 figured, fig. 20 measures 0*15 mm. in diameter, the medullary test 

 being 0-055 mm. in diameter, the spines 0*19 to 0*26 mm. long, 

 and 0-035 mm. thick. In fig. 21 the cortical test is 0*115 mm. 

 in diameter; the medullary test has not been preserved; the 

 spines are 0*1 to 0*15 mm. long, and 0*035 mm. thick. The 

 figured specimens are from volcanic tuff, No. 387 d ; similar forms 

 are also common in the dark siliceous limestones of the Temporary 

 Common, Tamworth. No. 245 3. 



Trilonche elegans, sp. nov. (PL" VIII, fig. 22.) 



The cortical test is only shown in section ; the wall is thin, with 

 small pores ; the medullary test is about half the diameter of the 

 cortical ; the pores are subcircular, with a delicate polygonal frame- 

 work. The radial spines are short, conical, nearly equal in length, 

 but at unequal distances apart. Diameter of test, 0*09 mm. ; of 

 inner sphere, 0*047 mm. ; length of radial spines, 0*04 mm. In 

 siliceous limestone. No. 245 3. 



Genus Acanthosph^ea, Ehrenberg. 



The test is a simple latticed sphere, with eight or more radial 

 spines of the same kind. 



Acanthosphjera australis, sp. nov. (PL VIII, fig. 23.) 



Only sections of this form are shown ; the spines are short, robust, 

 conical, and somewhat unequal in length, but of the same kind ; 



