THE FORAMINIFERA. 103 



able than their variety of form, which may well be called im- 

 mense, as no less than 2,400 living and fossil species have 



A Forammiferi (Rotalia ornataj with its filaments extended. 



already been distinguished by naturalists. Here we see a group 

 resembling exquisitely moulded flasks, or amphorae, with 

 beautifully fluted sides ; there another alternately dilating and 

 expanding like a string of chiselled beads ; whilst others again 

 exhibit the graceful spiral of the nautilus. 



One of their most striking features is their marvellous minute- 

 ness. Janus Plancus, who first discovered them in the strand 

 of Rimini, in the year 1731, counted about 6,000 of their shells 

 in a single ounce of drift-sand ; and Professor Schultze, of 

 Bonn, found no less than a million and a half in the same 

 quantity of pulverised quartz, from the shore of Mola di 

 Gaeta. The Globigerinse, which have been found in such vast 

 numbers in the bed of the Atlantic, are each about 1-5 Oth part 

 of an inch in diameter, and the linear dimensions of recent 

 British species are said by Professor Greene to vary from 

 1 -5,000th to 1-5 0,000th of an inch ! But the diminutive world 

 of the Foraminifera has also its giants, particularly among the 

 fossil species, such as the Nummulites, which occur in such 



