82 



THE OCEAN WORLD. 



this little creature was thought to be a polyzoon ; but d'Orbigny, 

 in his " Prodrome de Paleontologie," has correctly placed it among 



the Foraminifera, thinking that it 

 appeared to occupy a place be- 

 tween the two classes. 



Our exact knowledge of the 

 Foraminifera is of comparatively 

 recent date. Great numbers of 

 minute particles, of regular and 

 symmetrical form, were long dis- 

 tinguished as existing on the 

 sands of the sea-shore. These 

 early attracted the attention of 

 observers. But with the dis- 

 covery of the microscope, these 

 small elegant shells, which were 

 among the curiosities revealed by the instrument, assumed immense 

 importance. Linnaeus placed them with the beautiful genus Nautilus 

 as a group, which would include, according to that author, all the 

 multilocular shells. In 1804 Lamarck also classed them among 



Fig. 14. Fabularia discolithes (Defrance), 

 natural size and magnified. 



Fig. 15. Alveolina ovoidea (d'Orbigny), 

 natural size and magnified. 



Fig. 16. Dactylopora cylindracea (Lamarck), 

 natural size and magnified. 



the molluscous cephalopods. But Alcide d'Orbigny, who had devoted 

 long years to their study and observation, and may be considered 

 the great historian of the Foraminifera, showed that this method 

 of classification was inexact. Dujardin separated them altogether 

 from the class of molluscs, and showed that they ought to be con- 

 signed to a much lower class of animals. 



We have stated that the Foraminifera are of microscopic dimen- 

 sions. With some trifling exceptions, this is generally true ; but 



