4i8 



I.AUDF.RIA 



GENUS 87. LAUDERIA CLEVE, 1873. 



Fig. 136. 



Lauderia annulata. 



Frustules cylindrical, annulate ; valves 

 orbicular, covered, at least near the margins, 

 with numerous filiform processes or spines. 



The type-form of this genus is Lauderia 

 annulata Cieve, which is figured in the margin 

 (fig. 136), and which inhabits the Java Sea; 

 Lauderia delicatula was found by Stolterfoth, in 

 1879, on tne surface of the Dee, England. 



About a dozen other species have been described, but all those 



hitherto discovered belong to warmer regions than ours. 



Detonula Schutt (1893), * s a g enus created at the expense of 

 Lauderia, for forms with plane valves, without small spines, on the disc 

 surface. 



