Natural Mistory of East Finmark. 97 
base of each papilla is a pore in the calcareous front wall ” ; 
but he adds: “ It has usually been assumed that the radiating 
series of pores correspond with slits between the bars; but 
in C. radiata there can be no doubt that the pores are in the 
same radii as the membranous marginal spines.” ‘ The 
lateral junctions of the frontal bars are indicated by prominent 
radial ridges, each of which rises to a small tubercle just 
inside the line of the membranous papille above described. 
The pores consequently lie, as described by other observers, 
in radiating furrows. That the union between the bars has 
not been complete is indicated by the fact that a thin line of 
air im some cases underlies the ridge.’ Thus Dr. Harmer 
considers that this particular form totally differs from ordinary 
Cribrilinide in that the line of lacunes is here the centre of 
the bar, and that the ribs are its sides. My own conclusion is 
different. I regard these papille as really in the line of junc- 
tion of the bars. It is my endeavour to show in these notes that 
all the different Cribrilinidan forms depend upon the different 
structural building up of the bars which we first meet with 
in their simplest form in Lepralia nitida, and that the dars 
may be invariably recognized by their basal loop, which usually 
has its origin in the side wall; but in cases where the Cribrili- 
nidan structure occupies only the central part of the front wall 
the loop of the bar will be found buried in that front wall. If 
the illustration (PI. IX. fig. 3) which I have given of a portion 
of the front wall of innominata be now referred to, it will be 
seen that three bars are represented with their basal loops 
situated in the side wall, that at the inner end of the loop 
there is a minute pore, and a line passes down the centre of the 
bar indicating the lumen beneath*. Between the bars (that 
is, at their junction) is the usual line of lacunes; between the 
loops of the bars, and excluded from the normal Cribrilinidan 
structure by the fact that the arch which connects the bars 
passes inside them, are the papille (a, 0, &c.), which are thus 
in the line of, but really outside of the junction of the bars 
which form, the lacunes. If an opening (ec), from which 
the papilla has been removed, be examined it will be found 
to be inside of the side wall, and that it is directed inwards 
and downwards so as to pass into the body-cavity. Now if 
the bars and their lumen represent the spines of what have 
been called Membraniporide, and if the lacunes with the line 
which passes through them be the junction- line of two adjacent 
bars, then these papille cannot represent the spines. What 
are they then? Their resistance in boiling liquor potassze 
* The “thin line of air” which Dr. Harmer observed was, in my 
opinion, in this lumen. 
Ann. & Mag. N. Hist. Ser. 7. Vol. xii. 7 
