Oroup of Russian Fusulinir. 417 



tliat tlic ai)}):irent constriction of the j)articular specimen 

 ligurecl in the ' Mikrogcologic ' is due to external causes — in 

 otlii-r words, that the shell may originally have been cylin- 

 drical or nearly so. 



FiutitUna princeps (Ehrcnberg). PI. XVIII. fig. 5 («& 6?). 



Borili^ pn'ncfps, l^hronherp, Mikrogeologic, loc. cit. 

 jutUcosphtrra (!•'), id. ibid. 



The finer of the subsphorical modifications of the P^usuline 

 type, as found in the jliatschkovo beds, have the broadly 

 elliptical contour of F. princeps, a form well illustrated by 

 Klircid)erg's figure. The liorelis palausphivra of the same 

 author is re))resentcd in his j)latc by a cast of the interior of 

 a somewhat unsynuiiotrical specimen. The peculiarity in 

 this case is probably quite accidental ; and it is surely not 

 worth while to regard it as more than a mere individual 

 variation. 



In a paper on some fossil Foraminifera from Sumatra, 

 published last year in the 'Geological Magazine'*, I described 

 and figured certain large elliptical FusuUjkb as pertaining to 

 F. jninceps, their chief apparent divergence being in the 

 matter of size. Since then M. Jules Iluguenin has presented 

 a paper to the Geological Society of London f on the same 

 fossils, with the conclusion " that they belong to a new genus, 

 to which perhaps the North-American Fusulina rohusta also 

 belongs." I can find no sufficient reason for this decision, 

 either in respect of the Sumatran or the American species. 



Quite recently I have had the opportunity of examining 

 the extensive collection of Fusuliiue made by my friend Dr. 

 Guido Stache of Vienna in the Carpathian Mountains, and 

 the similarly beautiful series brought home by Dr. Richthofen 

 from China, at present in the hands of my friend Dr. Schwager 

 of Munich for description. These collections reveal new and 

 unsuspected modifications of the type to an extent that must 

 considerably alter our views as to its range of variation ; yet 

 I doubt if even they can be said to aftbrd ground for any true 

 generic subdivision. The extremes of variation in Fusulina 

 are scarcely wider apart than those of the isomor|jhous genus 

 Alvealina; and the successive links in the series are not less 

 closely connected. As in Alvcolina, some specimens have 

 thick, whilst others have characteristically thin shells ; one 

 set of varieties has simple chambers, another has the interior 

 of the segments more or less subdivided ; and, lastly, the 



• Geol. Mh^t. decade ii. vtd. ii. p. o!]2, j>l. 1.*]. tip. 0, a~c. 

 f" .luiu- 7, ly7('>. Paper not yet published in lull. 



