79 
Polyzoa , Annulosa , etc. 
well represented, also those of the Upper and Lower Silurian Gallery, 
strata. No. 8 
t he foreign species occupy Wall-cases Nos. 10 and 11. The Eas^side. 
.orach] opoda were most carefully studied by the late Mr. Thomas Wall-cases, 
iJavidson, LL.D., F.R.S., who devoted his whole life to the Nos - 10 and 
^lustration and description of this class of the Mollusca. 1L 
Many o± the specimens figured by him may be seen in the 
cases. In 1886 he bequeathed his entire collection to the 
JNcilion, and it is exhibited in Gallery No. 11. 
Class 6. Polyzoa (Sea-mats and horny Corallines). 
These elegant organisms, so frequently found upon the sea- Table-case, 
shore, and often confounded with sea-weeds (Algae), are really £L°* 84 - 
01 _ calcareous composite habitations of numerous No l2 aSe 
distinct but similar microscopic zooids, each individual occupy- 
ing a minute double-walled sac, in a common habitation, called 
a ccencecium. 
They are met with in great variety of form in the Coralline 
Ciag of Suffolk, in the Miocene of Dax, Bordeaux, and Touraine 
and more rarely in the Eocene beds of the London and Paris 
Basin. 
, Beautiful masses of Fenestella are found in the Permian or 
Magnesian Limestone of Durham, and in the Permo-Carboni- 
ferous rocks of Australia and Tasmania. The Polyzoa of the 
Carboniferous formation are also numerous and varied. The 
most singular of these is the Archimedipora, which has its 
ccencecium, or polyzoarium , arranged around a central screw-like 
axis, giving it a most elegant geometrical form. 
Sub-Kingdom 2. — Annulosa. 
Division A.— Arthropoda (Jointed Animals). 
Class 7.— Insecta (ex. Beetles, Flies, Bees, &c.). 
y> ^ • Myriapoda (ex. Centipedes, Millipedes). 
” Arachnida (ex. Spiders, Scorpions, &c.). 
Insects, Myriapods, and Arachnida are very rare in the rock- Insects, 
formations of this country. They have, however, been met 
with in considerable numbers in the Eocene strata of Gurnet 
Bay, Isle of Wight, in the Purbeck Beds of Swanage, Dorset, in 
the Great Oolite of Stonesfield, the Lias of Warwickshire, the 
Coal Measures of Coalbrook-dale, and Scotland, &c. (see Table- 
case No. 84). They are more abundant in the Browm Coal of Table - c ase, 
Bonn ; in the Amber from the Miocene Beds of Samland on the N °' 84 ‘ 
Baltic ; from CEningen, near Constance ; and from the Litho- 
