1895.] MICKOSCOPICAL JOURNAL. 83 



60. TRIGONACTURA. 



Arms without terminal spine, nearly square pythagorae. 



Arms without terminal spine, club-shaped rhopalastrella. 



Arms with terminal spine, triangular trigonodiscus. 



Arms with terminal spine, club-shaped trixiphos. 



61. HYMENACTURA. 



Arms without terminal spines, nearly trapezoidal pythagorfe. 



Arms witliout terminal spines, slender, lanceolate trigona. 



Arms without terminal spines, nearly equilateral triangular hexagona. 



Arms with terminal spines, nearly square ptolemaji. 



62. ASTRACTURA. 



Arms without terminal spine, trapezoidal, 0.05 long ordinata. 



Arms without terminal spine, nearly tranezoidal, 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 2-25 on each ring orbiculatus. 



Eight rings concentric ; pores 11-2 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 I5-2 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. 



detbrmis. 



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 spiiale. 



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. 



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



