the Valves of Rhynchopora Geinitziana. 231 
make additional observations on some specimens from Gera, with 
one of Smith and Beck’s highest-class binocular microscopes, 
for the use of which I am indebted to its owner, Dr. Rowney. 
I shall now relate the results of my last investigations. 
In order to ensure an examination of the entire thickness of 
the valves, I operated on specimens partially imbedded in their 
matrix, which is siliceo-caleareous and granular. 
Figure ] represents a polished medio-longitudinal section of 
one of these specimens, about thrice its natural size. The in- 
terior is filled with calcite. The letter a refers to the matrix, 
which adheres to a considerable portion 
of the perforate valve. In this case, Fig. . 
there can be no doubt that the extra- OM 
neous mineral matter covers the ori- Cae 
ginal outer surface of the fossil. At the ie 
umbonal region, b, the external layers 
of the test are not present, having got 
detached along with the matrix before 
the specimen came into my hands: the 
surface exposed at this part, as well as that of the imperforate 
valve, displays numerous dark-coloured spots, resembling those 
resulting from tubulation in many Palliobranchs, particularly 
the Carboniferous Spiriferina octoplicata, 1 which, however, 
they are larger. 
Figure 2 represents a portion, from below the letter a, of the 
last section, as seen under a mag- Fig. 2. 
nifying power of 120. Two of the ¢- 
tubes are insufficient for our pur- 
pose, having been broken short of 
their length by the removal of the 
outer layers and matrix; but the 
next one is conclusive, as it passes 
completely through the valve. The 
fourth or adjoining tube does not appear to reach the ex- 
terior. 
Figure 3 represents a portion of a similar longitudinal sec- 
tion, as seen under the same power. It shows two tubes tra- 
versing the thickness of the valve Fig. 3. 
to the outer surface, and a third one ~~» 
apparently passing to within a very 
short distance of it. I strongly sus- 
pect that the last tube, as well as the 
“fourth” in fig 2, is not in reality 
any shorter than the others, because 
precisely where it appears to termi- 
nate the test loses its semitransparency (brought out by the 
