Lower Paheozoic Rocks of the South of Scotland. 49 



the outer, so that in section the outer spliere has the appear- 

 ance of an encircling ring. The framework of both outer and 

 inner spheres apparently similar. No central medullary shell 

 can be recognized. The minute structure of the raeshvvork is 

 obscured by the dark infilling. Diameter of outer sphere 

 '25, of the inner "15; length of radial beams "015 millim. 

 Rare. 



Distrihution. Abington, Lanarkshire ; Hartree Hill, 

 Peeblesshire. 



Family Staurosphserida, Ha^ckel. 



Sphffiroidea with four radial spines on the surface of the 

 spherical shell, forming a regular cross, being opposite in 

 pairs in two axes perpendicular to one another. (Chall. Rep. 

 pt. i. p. 151.) 



Genus Staurodoeas, Hseckel. 



Staurosphserida with spongy spherical shell and four crossed 

 simple spines. (Chall. Rep. pt. i. p. 168.) 



Staurodoras gracilis, sp. n. (PI. IV. fig. 7.) 



The siliceous mesh apparently of a close irregular character, 

 with apertures of about -01 millim. wide. The radial spines 

 slender, evenly tapering, about two thirds as long as the 

 diameter of the shell. In the specimen figured one of the 

 spines has been broken off. Diameter of the sphere '11 j 

 length of spines 0*7, thickness at base '01 millim. Another 

 specimen has the spines stouter, measuring "02 millim. at the 

 base. 



Three species of this genus have been described by Duni- 

 kowski * from the Lower Lias of Schafberg, near Salzburg ; 

 but in these the siliceous framework appears to be more 

 regular and the spines stouter than in the present species. 



Distrihution. Abington, Lanarkshire ; Hartree Hill, 

 Peeblesshire. 



Genus Stauroplegma, gen. nov. 



Staurosphjerida with solid, irregularly reticulate or spongy 

 vshell, a concentric medullary shell, and four simple spines 

 approximately in the form of a cross. This genus differs 

 from Staurodoras by the possession of an inner medullary 

 test. 



* Denksclir. d. k. Akad. d. Wiss. Wien, Bd. xlv. p. 188, pi. v. fi^-a. 56, 



57,58. 



Ann. & Mag. N. Hist. Ser. 6. Vol vi. 4 



