OF THE REGULAR ECHINOIDEA. 371 
PLATE L. 
Fig. 1. Spicula from ambulacral tube of Heliocidaris ? 
Fig. 2a. Spicula from ambulacral tube of Echinus sphera ; b, from ovary. 
Fig. 3a, b. Ditto, ditto, E. Dröbachiensis. 
Fig. 4a. Edge of large spiculum of Heliocidaris, showing the tubular and reticulate character of the 
areola ; 5, side view of smaller spiculum ; c, Hooked spicula from base of ambulacral tube. 
Fig. 5 a. Spicula from the ambulacral tube; 5, internal membrane from near the anus; c, from ovary, 
of Echinus from Aneiteum, New Hebrides. 
Fig. 6a. Spicula of an ambulacral tube of Acrocladia trigonaria ; b, from ambulacral vessel. 
Fig. 7. From ambulacral tube of Podophora atrata. 
Fig. 8a. From ambulacral tube; 5, intestine ; c, ovary of Mespilia. 
Fig. 9. Spicula from Temnopleurus. 
Fig. 10a. Tentacular (?) spicula of Chirodota; b, Synapta, from Japan. 
Fig. lla. Miliary plates of Synapta inherens; b, ditto Synapta from New Zealand; c, ditto Synapta 
digitata ; d, S. bidentata (c & d, after Woodward and Barrett). 
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