4 
SECOND YARKAND MISSION. 
sides and on the edge of the bases of some of the papillae, tubercles and warts of other types. 
Their resemblance to minute oscula of sponges is superficially evident ; hut it is to be shown 
that one great group of the fossils under consideration does not possess them, that they differ 
in their number in different parts of the same fossil and in different individuals of the same 
species. I have called them “ pores,” and their absence in one of the groups of the fossils 
has led me to divide these Karakoram Syrmgosphcerida into two genera one with pores on 
the outer surface is termed Syrmgosphceria, and that without pores I have dedicated to 
Stoliczka’s memory, terming it StoUczkaria. 
The method of examination of the fossils is necessarily a simple one. Their surfaces are 
usually well preserved and not over-weathered, and the insides, in the majority of instances, 
yield good sections, both radial and tangential. Careful washing adds to the details of the 
surface, and biting with hydrochloric acid and water is necessary to distinguish tube structure 
from the intertubular calcite of fossilization which sometimes simulates it. 
The sections, on account of the brilliant opacity and white or wliite-brown colour of the 
tubes, can be well studied by reflected light, and indeed it is advisable to do this preparatory 
to the examination by transmitted rays. The dilute acid is very useful in some confused 
sections, for it dissolves the infiltrated calcite which exists between the tubes, and leaves their 
granular wall to a certain extent untouched. The paths of tubes can then be seen by 
reflected light very well. If the acid is allowed to act too strongly, all structure disappears. 
The tubes, both radial and interradial, are easy to see in the majority of instances, but 
in one particular case polarized light and the selenite plate determined the visibility of the 
structures, which were hidden amongst a confused mass of calcite. The calcite which was 
introduced during fossilization fills the tubes as well as their interspaces, and it has taken on 
definite or indefinite cleavage planes. These must be studied under polarized light, for the dark 
lines they produce to ordinary transmitted light, and which simulate ccenenchymal structure 
can then be decided to be only divisions between crystals or parts of different nolariVirm 
influence on the ray. 
Low powers of the microscope suffice for most of the examination, but a good i-ffich 
object glass is required to distinguish the granules and granule-spiculate elements of the 
tubes. 
No other form of fossilization but that by calcite has been noticed, and silica does not 
enter into the composition of the bodies. 
On examining the surface of a rugged or tuberculate specimen of either of these genera 
with a hand lens, a reticulate appearance is seen between the projections. In very good speci- 
mens, on the ordinary level of the surface, after biting with dilute acid, or sometimes without 
this proceeding, this reticulation resolves itself into a gyrose tubulation ; the tubes coming to 
the surface, running along it in close proximity, dipping down again suddenly and re-appear- 
ing* an< l sometimes bifurcating. Between the tubes is a more or less linear interspace filled 
with dark calcite. "Weathering sometimes has destroyed the tubulation and left the thin 
interspace to look like a mesh, or the interspace has been left void, the tubules remainin' 1. 
Besides this reticulation, there are in some types numerous, and in others but a few 
minute openings from to 3 *-^ inch in diameter, and they have a margin or tube layer. 
They are sometimes separate, and at others they are clearly the outside opening of one of the 
superficial tubes just mentioned. Usually the caliber of the tubes is filled 'with brownish 
coloured calcite, or with granular carbonate of lime, but in some instances the presence of a 
very delicate tube wall, unattached by its outside to any structure, is evident. 
