Bd VI: 4) THE ECHINOIDEA. 97 



Those below the petaloid part contain numerous spicules. The subanal tubefeet are 

 rudimentary. In the tubefeet round the peristome the spicules are richly developed; 

 they have the form of slender, slightly branched rods (PI. XIX. Fig. 9). The rods 

 supporting the filaments of these tubefeet are somewhat thick, but otherwise of the 

 common simple structure. 



The pedicellariae are represented by three forms, viz. globiferous, rostrate and 

 tridentate. The globiferous pedicellariae (PI. XIX. Figs. 3, 14, 20, 24) are generally 

 very conspicuous, longstalked and with the head and the upper end of the stalk 

 enclosed in a thick, probably glandular, coat. The valves end in two (seldom three) 

 long teeth, gently curved at 'their base. The blade is narrow, with a long slit in 

 the outer half, the lower part being a closed tube; its lumen continues some way 

 down into the basal part. There is no neck; the stalk has a little swelling, where 

 the muscles from the head are fastened, otherwise without widenings; it is of rather 

 compact structure. This form of pedicellariae is especially numerous along the petals. 

 (In Abatus cavernosas var. bidens a quite similar form of globiferous pedicellariae is 

 found; cf. above p. 73, PI. XIX. Figs. 32, 39.) — The rostrate pedicellariae (PL XIX. 

 Fig"- I 9) are very like those of Abatus; they are rather small, only ca. 0.2-3 mm. 

 length of head. The tridentate pedicellariae (PI XIX. Figs. 13, 23, 25, 27) are three- 

 valved, seldom two-valved; they reach a rather large size, up to 0.8 mm. length of head. 

 The valves "join only in the outer part, in about one third of the length of the blade; 

 below they are widely apart. The outer part of the blade is widened, with finely 

 serrate edges, the lower part is narrow, forming a closed tube below, with a broad 

 slit continuing down from the widened part. The border between the two parts of 

 the blade is sharply marked, the side edges being bent inwards over the blade and 

 making rather sharp corners. The edges of the lower part of the blade are smooth, 

 as are also the edges of the basal part and the apophysis. The neck is well devel- 

 oped, except on the largest specimens, where it may be almost wanting. The stalk 

 is compact, with no distinct widenings. In the smaller tridentate pedicellariae the 

 narrow part of the blade becomes gradually shorter, and the quite small ones are 

 simply leafshaped (PI. XIX. Fig. 8). These latter may equally well be termed tri- 

 phyllous pedicellariae. — The sphaeridiae are round, rather much grooved (PI. XIX. 

 Fig- 4)- 



As stated above, the females have their petals transformed into marsupia, and, 

 fortunately, the embryos were also found in the marsupia. As in Abatus caverno- 

 sus, I have found both eggs and large embryos, almost fully developed, in the same 

 marsupium; in one I counted 7 eggs and 10 embryos, in another marsupium 11 eggs 

 and 6 embryos. The eggs are yellow, evidently very rich in yolk, 1 mm. in dia- 

 meter. Most of the embryos were about 2 mm. long, a few of them a little smaller 



13 — 100133. Schivedische Siidpolar-Expedition igoi — /goj. 



