1893.] MICROSCOPICAL .TOURNAL. 257 



Spines united by ring. Saturnalis. 



B. — TWO SPHERES. 



Spines equal. Stylosphiera . 



Spines different. Sphaerodylus. 



3.— Family: STAUROSPH^.RIDA. Four radial spines 

 forming a cross. 



A. — ONE SPHERE. 



All four spines equal. Stanrosphxra. 



B. — TWO SPHERES. 



All four spines equal. Staurulonche . 



Four spines different in pairs. Staurolonchidium. 



C. — THREE SPHERES. 



All four spines equal. Stauracontmm. 



4.— Family: CUBOSPHvERIDA. Six radial spines oppo- 

 site in pairs. 



A. — TWO SPHERES. • 



All six spines equal and simple. Hexalonche. 



B. — THREE SPHERES. 



All six spines equal and simple. Hexacontium. 



5.— Family : ASTROSPH^RIDA. Eight to twelve or more 

 radial spines. 



A. — ONE SPHERE. 



Spines all of same kind and simple. Acanihosphxra. 



B. — TWO SPHERES. 



All spines equal and simple. Haliomma. 



C. — THREE SPHERES, 



Spines equal. Actlnomma. 



Larger and smaller spines. Eckinomma. 



XL— ELLIPSOIDAL SHELLS. 



Here are 19 genera which fall into 3 sections according to the 

 number of chambers. 



A. — One Chamber. 



6.— Family: ELLIPSIDA One shell. 



Radial spines. Ellipsidium. 



No radial spines. Cenellipsis. 



Polar spines. Ellipsoxiphus. 



Spines at one pole only. Lithomespilus^ 



