308 CORRESPONDENCE, 
small as one 200,000th of an inch is a conclusion which can be re- 
futed without the slightest difficulty.” A few years ago Mr. Huxley 
said in substance, at a meeting of the London Microscopical Society, 
that if the opticians could not supply microscopes that would enable 
one to see spaces between objects one 100,000th of an inch apart, 
naturalists were at the end in that direction of their work. It was 
replied that American and London opticians had already supplied 
instruments that had separated lines but one 224,000th of an inch 
apart. 
CORRESPONDENCE. 
THe LATE Proressor Cu. G. Enrenpera’s RESEARCHES ON THE 
Recent AND Foss, FoRAMINIFERA. 
To the Editor of the ‘ Monthly Microscopical Journal.’ 
Srr,—The following observations on Dr. Ehrenberg’s researches 
may not be uninteresting to your readers.* 
Amongst the most enthusiastic observers and voluminous writers 
on microscopic organisms, Dr. Ehrenberg stands pre-eminent. By 
the end of the year 1838 he had reduced to order the multitudinous 
specimens of recent and fossil Microphytes and Microzoa which he 
had either collected, with Dr. Hemprich, in the East (Egypt, Dongola, 
Syria, Arabia, and Abyssinia), or had received from numerous corre- 
spondents. 
In the ‘Transactions of the Berlin Academy of Sciences’ for 1831, 
1832, and 1838, Dr. Ehrenberg published the results of the researches 
made on Corals and associated animals by Dr. Hemprich and himself 
in 1823-25 among the islands and coral-banks, and along the coasts 
of the Red Sea. In this memoir, after reviewing the systems of 
classification adopted by his predecessors, he separated the Coral 
animals into Anthozoa (flower-animals) and Bryozoa (moss-animals) ; 
and the former he divided into Zoocorallia (comprising Polyactinia, 
Octactinia, and Oligactinia), and the Phytocorallia (comprising Poly- 
actinia, Dodecactinia, Octactinia, and Oligactinia). Altogether he 
enumerated 386 living species, of which 110 he had himself observed 
in the Red Sea. The range of Corals and their occurrence in the 
fossil were also noticed. 
The classification here alluded to has been superseded by others 
based on a still more intimate knowledge of the structure and phy- 
siology of the Celenterate groups—Hydrozoa and Actinozoa; whilst 
the classification of his “ Bryozoa” (Polythalamia,t Gymnocore, 
Thallopoda, and Scleropodia), mingling Foraminifera and Polyzoa, 
* These remarks are based on some critical notes on Ehrenberg’s species of 
Foraminifera in the ‘Annals and Mag. Nat. Hist.’ Ser. 4, vols. ix. and x. 
+ Ebrenberg’s “ Polythalamia” (divided into Monosomatia and Polysomatia) 
consist of Forumimifera with some Polyzoa. 
