FORAMINIFERA. 89 



Great numbers of minute particles, of regular and symmetrical form, 

 were long distinguished on the sands of the sea shore. These corpus- 

 cular atoms early attracted the attention of observers. But with the 

 discovery of the microscope, these small elegant shells, which were 

 among the curiosities revealed by the instrument, assumed immense 

 importance. We have stated that these corpuscles are nothing but 

 the shell or solid framework of a crowd of marine animalculse : we 

 may then consider them as living species analogous to the Ammonites 

 and Nautilus of geological times. Linnaeus has placed them in this 

 last genus, which would include, according to that author, all the 

 multilocular shells. In 1804, Lamarck classed them among the 

 molluscous cephalopods. But Alcide d'Orbigny, who has devoted 

 long years to study and observation, and may be considered the great 

 historian of the Foraminifera, makes it appear that this mode of 

 classification was inexact. Dujardin separated them altogether from 

 the class of mollusks, and showed that they ought to be consigned to 

 an inferior class of animals. These minute creatures, in short, are 

 deficient in the true appendages analogous to feet, which exist in the 

 higher mollusks. They simply possess filamentous expansions, very 

 variable in their form. 



We have stated that the Foraminifera are of microscopic dimensions. 

 With some trifling exceptions, this is generally true ; but there exist 

 a number of species which are visible to the naked eye. The Fora- 

 minifers found in the nummulite formation of Tremsted, in Bavaria, 

 between Munich and Saltzberg, are still larger, being nearly double 

 the size of the nummulite of the Pyramids ; in short, they are the 

 giants of this tribe of animals. 



After these remarks, we may venture to give some idea of the 

 structure and classification of these beings, whose part in the work of 

 creation has, in former times, been so considerable. 



The bodies of the Foraminifera are formed of a gelatinous sub- 

 stance, sometimes entire and round, sometimes divided into segments, 

 which can be placed upon a line, simple or alternate, wound up into 

 a spiral form or rolled round its axis, like a ball. A testaceous envelope, 

 modelled upon the segments, follows the various modifications of form, 

 and protects the body in all its parts. From the extremity of the 

 last segment of one or many openings of the shell, or of the numerous 

 pores, issue certain long and slender filaments, more or less numerous, 



