80 GUIDE TO THE FOSSIL INVERTEBEATE ANIMALS. 



Oligocene of the Isle of Wight. 



The Eunice found in 



Gallery 



Wal?case ^o^^^^® Pleistocene age from Greenland shows how well 



15A. 



Fig. 37. — A worm-casting from the Kimmeridgian Lithographic Stone near 

 Solenhofen, Lumhricaria 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 1735, is on the middle slope of Wall-case 15a. 



the Errantia can be preserved when circumstances are favour- 

 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 



■TTTTT J- «/ 



East Side Arthropoda, that great group of the animal kingdom 



Table-cases which includes insects, centipedes, lobsters, barnacles, spiders, 

 25-20. scorpions, and a host of less familiar forms. These animals 

 "^14-12^^^ have no internal skeleton, but the body is enclosed in a case 

 made of a horny substance called chitin. In the island of 

 Oesel thin films of this substance, the former clothing of a 

 marine arthropod, have been preserved without change since 

 Silurian times. Sometimes lime salts are deposited in the 

 chitinous envelope, and render it even more fit for preser- 



