144 The American Geologist. September, 1900 
its connections with adjacent plates, from the same specimen 
(PI. XVI, fig. 16). 
Fig. 4, Decadocrinus gra?uiis W. & Sp., shows a few 
pores at the sides of the hexagonal plates in the sac. Many 
more might have been shown if a specimen had been selected 
with special reference to them, for they are more or less 
plainly visible in eleven specimens in my possession. I have 
figured the distal portion of the sac in one of them, showing 
the pores at the middle of the sides of the plates. (PI. XVI, 
fig. 17). 
2. Are there Pores piercing tJie Sac in certain Fistula taf 
The facts already given in confirmation of the figures and 
statements contained in our Monograph would seem to be 
sufficient to settle this question in the alihrmative. But this is 
by no means all the evidence at my command, and I will give 
some additional proof which will be convincing to all stu- 
dents, including, I think, Mr. Bather himself. 
In the first place, I wish to illustrate a form of apparent 
apertures in the sac, somewhat different from most of the 
preceding ones, viz.: elongate fissures. These are best 
shown in the upper part of the sac in Scaphiocrinus missoiiri- 
ensis, from the St. Louis limestone. We figured the lower 
part of a specimen of this species (Monog. PI. VII, figs. la, b) 
for the purpose of showing the location of the anal opening. 
I give an enlarged figure (PI. XVI, fig. 15) of a plate and 
connections, from the sac of another specimen. It will be 
observed that these plates do not have distinct pores at the 
sides, but narrow parallel fissures passing from one plate to 
another, crossing the sutures at right angles, and at the middle 
of the sides — not at the angles. These fissures are not a mere 
surface ornamentation, but in this specimen are filled with 
a substance darker than the test, just like that which fills 
the pores in the other specimens. Upon a careful examina- 
tion of a number of specimens, with a strong magnifier and 
good light, I am convinced that these fissures do actually 
penetrate through the plates to the interior. There is a de- 
pression at the side of each plate, it is true, toward the suture, 
but the fissures cross the depressions and extend nearly to 
the middle of the plates. The plates at this part are extreme- 
