14 GUIDE TO THE FOSSIL INVEETEBEATE ANIMALS. 



Gallery XI. Several of these have a curious structure which produces in 

 them a close resemblance to the skeletons of corals. Some 

 larger masses of rock exhibiting the same structure are in 

 the IST.E. corner of the Gallery. 



Further examples of concretions and other markings 

 produced in various ways, not themselves organic, but 

 curiously simulating organic objects, such as a human 



Wall-case skull, the tooth of an elephant, a dog's head, plants, and 

 fruits, are exhibited in order to impress upon beginners in 

 the study of fossils the truth that here, if anywhere, things 

 are not always what they seem. 



The term " fossils," as has already been said, is applied 

 not only to the remains of animals and plants, but to various 

 traces left by them. The footprints of many animals with 

 which we are more or less familiar are easily recognised, and 

 many such exhibited in Wall-cases 8, 9, and 10 on the east 

 wall are described in the Guide to the Fossil Pteptiles. The 

 more lowly animals, however, produce tracks which are less 

 well known, and while certain markings found in the rocks 

 can reasonably be explained by reference to the tracks and 

 imprints of animals or plants now living, others still lack 



Wall-cases a convincing explanation. Here may be seen tracks 

 ^' ascribed to marine worms, crustaceans, and jelly-fishes ; 

 others, which have been ascribed to fossil plants and have 

 received learned names accordingly, are now supposed to 

 be either the tracks of some animal, such as a worm, or 

 even the markings left by currents or eddies in the water. 



Wall case Markings obviously ascribable to such inorganic agencies — 

 for example, ripple marks and the prints of rain drops — have 

 been found in rocks of all ages, appearing just like the 

 " ribbed sea sand " of to-day, or the rain prints newly formed 

 on any wet surface of mud or sand, such as the stretches left 

 when the tide goes out at the Bay of Fundy. 



PROTOZOA. 



Gallery X. Entering Gallery X, either from that last described or from 

 the Gallery of Fossil Eeptiles, No. lY, we pass down its left or 

 western side to the far end. Here are exhibited the remains 

 of the lowest forms of animal life that are preserved as 

 fossils. These are the Foraminifera and the Radiolaria, two 

 sections of the Phylum or great group Protozoa (first, i.e. 

 simplest, animals). 



