1895.] MICROSCOPICAL JOURNAL. 83 



60. TRIGONACTURA. 



Arms without terminal spine, nearly square pythagorse. 



Arms without terminal spine, club-shaped rhopalastrella. 



Arms with terminal spine, triangular trigonodiscns. 



Arms with terminal spine, club shaped trixiphos. 



61. HYMENACTURA. 



Arms without terminal spines, nearly trapezoidal pythagorse. 



Arms without terminal spines, slender, lanceolate trigona. 



Arms without terminal spines, nearly equilateral triangular hexagona. 



Arms with terminal spines, nearly square ptolema;!. 



62. ASTRACTURA. 



Arms without terminal spine, trapezoidal, 0.05 long ordinata. 



Arms without terminal spine, nearly trapezoidal, 0.1 long aristotelis. 



Arms without terminal spine, club-shaped clavigera. 



Arms with terminal spine, about twice as long as broad democriti. 



63. PENTACTURA. 



Arms nearly square pentactis. 



64. PORODISCUS. 



Nine rings concentric ; pores 2-22 on each ring orbiculatus. 



Eight rings concentric ; pores 12-2 on each ring concentricus. 



Six rings concentric ; pores 2-3 on each ring heterocyclus. 



Five rings concentric ; pores 1 on each ring macroporus. 



Eight rings spirally convoluted ; pores l2-2 on each ring spiralis. 



Four rings in a double spiral ; pores 2-3 on outer rings bispiralis. 



Four rings partly concentric, partly spiral ; pores 2-6 on different rings. 



deformis. 



Six rings partly concentric, partly spiral ; pores 2-4 on each ring... irregularis. 



65. PERICHLAMYDIUM. 



Rings concentric ; pores about 2 on each ring prsetextum. 



Rings convoluted ; pores 3 on inner ring spirale. 



66. OMMATODISCUS. 



Disk elliptical ; 5 chambered rings round central chamber fragilis. 



67. STAURODICTYA. 



Sixteen rings ; margin between spines dentated grandis. 



Eight rings ; margin between spines ciliated splendens. 



Four rings ; margin between spines smooth ocellata. 



68. STYLODICTYA. 



All rings concentric ; 8-12 spear-shaped, sulcated spines hastata. 



All rings concentric ; 8-12 or more bristle-shaped spines gracilis. 



AH rings concentric ; 24-30 or more bristle-shaped spines .multispina, 



