76 POPULAll HISTOrvY OF THE AQUARIUM. 



Paris is built is composed, to a great extent, of their shells. 

 Hundreds of thousands of specimens may be counted in an 

 ounce of sand ! 



The Foraminifera may be seen in a living state by taking 

 up seaweeds and branching Zoophytes, in favourable parts 

 of the southern coasts, at or near the edge of the tide. If 

 tliese are sliaken over a vessel of water, the Foraminifera 

 will first drop to the bottom, but will afterwards be found — 

 by help of a lens — crawling about or sticking to the sides 

 of the vessel. Many of them may also be picked up by 

 careful research among the patches of drifted sand and 

 shells which the tide will sometimes leave upon the shore. 

 Some of them are like flasks or bottles, and others like 

 twisted SerpulcE ; some are like Nautili j others like jointed 

 branches of coral. The principal genera are, — Lagena, the 

 flask-shaped form with a neck; Fntosolenia, also bottle- 

 shaped, but the neck doubled back as it were within the 

 body; Botatia, whose shell consists of a spiral arrange- 

 ment of swelled lobes ; Poli/stomella, shaped like a Nau- 

 tilus ; and some others. 



According to Dujardin, who has rather minutely examined 

 the history of the Foraminifera, they have not any distinct 

 organs of locomotion, although the film-threads thrown out 



