The 10 µm scale bar applies to figs. 1-5; the 100 µm scale bar applies to figs. 6-10a,b.
Figs. 1-4, 6-9. Merosiphonia socialis. Note differences in size and shape of smaller pores. Larger small pores funnel inwards (figs. 1-3) while the smallest have a raised rim (fig. 5). Note link between shell size and length of tubes: the larger the shell, the shorter the tubes (see also plate 11). Figs. 1, 3: forma compacta, fig. 2: forma socialis; figs. 4, 6-9: forma polysiphonia. BSS 28B(VIII/713, 792, 786, 793, 950); IOW 156(F); BSW P7(F) EF J26; BSS 111B(F) EF Q43; BSS 34B(F) EF T 35 and
Figs. 5, 10: Merosiphonia magnisphaera. Shell is much thinner than that of M. socialis. Fig. 10a focussed on the outer rim; fig.10b focussed on the surface of the shells. 28B(VIII/950) and IOW 150.