80 GUIDE TO THE FOSSIL INVEETEBHATE ANIMALS. 
Gallery 
VIII. 
Wall-case 
15A. 
Oligoceiie of the Isle of Wight. The Eunice found in a 
nodule ot Pleistocene age from Greenland shows how well 
Fig. 37 . — A worm-casting from the Kimmeridgian Lithographic Stone near 
Solenhofen, L^imbricaria colon. This is a facsimile of the engraving 
in Baier’s “ Oryctographia Norica,” supplement, plate VI., Fig. 6, 
published in 1757. The actual specimen, collected by J. J. Baier 
before his death in 1736, is on the middle slope of Wall-case 15a. 
the Errantia can be preserved when circumstances are hvvour- 
able. The rarity of such fossils proves once again the 
extreme imperfection of the geological record. 
ARTHROPODA. 
Gallery Next to the Annelida there are displayed the fossil remains 
Ea^t S^de Arthropoda, that great group of the animal kingdom 
Table-cases '"'hicli includes insects, centipedes, lobstere, barnacles, spiders, 
25-20. scorpions, and a host of less familiar forms. These animals 
^1412^^^ have no internal skeleton, but the body is enclosed in a case 
made of a horny substance called chitiu, which is not readily 
attacked by the ordinary acids or alkalies that percolate 
through the rocks. Sometimes lime salts are deposited in the 
chitinous envelope, and render it even more fit for preser- 
