Royal Physical Society. 151 
shells, uniting with each other, and forming glairy masses, and reticula- 
tions, and expansions, which absorb animal matter coming in contact 
with them,—single and compound animals building their aggregated 
homes in the most graceful lines and spirals,—single dwellings and 
populous towns slowly moving along, of which the inhabitants are but 
patches of transparent slime,—vast Polythalamian cities, where the huge 
primordial Rhizopods reign, surrounded by the multitudes of their 
dwarfed descendants, in widening circles and triple tiers. Such is Rhi- 
zopod life. At present, no true generative elements have been re- 
corded as discovered in the Rhizopods, though Carpenter and Schultze 
have noticed bodies which they have suspected to be ova. In the 
autumn of 1859, I was preparing a number of specimens of Hydrac- 
tinia for the microscope. They were first soaked in whisky for 
several weeks, then immersed in dilute nitric acid to remove them 
from the crab’s shell, and finally washed in strong spirit, and put 
up in Canada balsam. On examining one of these preparations under 
the microscope, it was found that two specimens of Truncatulina 
had been accidentally prepared at the same time. The development 
of Truncatulina commences with a single cell; this multiplies by gem- 
mation in series until a colony of animals is formed, each larger than 
its predecessor, arranged in a spiral, somewhat resembling the shell of 
the nautilus. In the nautilus, the last chamber of the shell only is 
occupied; but in Truncatulina every chamber contains its tenant, while 
the whole colony are united by a band of sarcode, which passes from 
chamber to chamber along the inner curvature of the shell. All the 
cells or houses in this Rhizopod town are full of minute pores, from 
which the inhabitants protrude their delicate arms of slime in search 
of prey, or to move the assemblage from place to place. When the 
Truncatulina is treated as before mentioned, the shell is removed, and 
the separate zooids appear united by their connecting band. One of 
the two Truncatulinas, when examined by aid of the microscope, was 
found to consist entirely of homogeneous matter; but the other presented 
a far different appearance. Its segments or zooids, and their connecting 
bands, all appeared to be inclosed in a well-defined membrane. Each 
segment was nearly destitute of sarcode, and contained a highly refractive 
body, in which appeared, with the utmost distinctness, a germinal vesicle 
or spot. I can regard this body only as a true egg, which has been deve- 
loped at the expense of the sarcodal element of the segments, in all of 
which the reproductive process is occurring simultaneously. Yet it may 
be objected that the ova in the larger segments are greatly larger than 
the young or original animals of Truncatulina, In some animals, how- 
ever, as in Spongilla, Gregorina, &c., many individuals are produced from 
a single egg ; and it is not improbable that a process of great division of 
the egg or swarming may take place in Truncatulina, by which a great 
number of animals are produced from each segment. 
2. Mr R. H. Traquarr exhibited some specimens of Trilobites from the 
Carboniferous Limestones of Fifeshire. 
3. Note on the exposure of the Liberton Old Red Sandstone Conglo- 
merate Bed, in a quarry recently opened near the Grange House, 
Newington. By Anprew Taytor, Esq. 
4, On the occurrence of the Argentine, Anchovy, and other Fishes, on the 
Coast of Caithness ; with a note on the termination of the Vertebral 
Column in the tarls of the Salmon tribe. By Cuartes W. Praca, 
Ksq.. Wick. 
