A CONTRIBUTIOX TO THE GENUS FUSULINA. 7 



limestone block tbuiul in a Shiwon-ciitting near Sakawa, province 

 of Tosn. In inicroseopic sections, it almost always happens that 

 the thin nppcr layer of the wall together with the median lamellae 

 is stained deep brown, while those parts of the walls and the 

 septa Avhich appear to be thoroughly perforate, rem;iin almost 

 unstained. This fact seems to be in favour of the view that the 

 median lamellae of the septa and the covering layei' of the wall 

 are of a different nature from the rest of the shell; but from this, 

 I would not directly conclude the non-porosity of the shell. 



ScHELLWiEX made mention of a particular case of the for- 

 mation of septa in Schwagerina of the group of Schwagerina 

 Verbcehi, savins: "Es tritt nämlich liüufio; eine Verdickuns; des 

 Septums ein, ehe die neue Kammerw^and gebildet Avird, wodurch 

 bei der geringeren Stärke des Septums leicht der Anschein erweckt 

 werden kann, da^s die Scheidewand eingekeilt wäre. Diese Ver- 

 dickung legt sich als ein dünner Beleg über das Septum."^* 



Taking these points in consideration, it appears to me that 

 the whole external surface of the shell and of the septa of some, 

 if not all Fasulina, is covered with a thin exogenous shell layer 

 as in some other highly organized Foraminifera (for example, 

 some species of the Genus Rotalia). 



Foui'thly, the infolding of the septa seems sometimes, though 

 probably seldom, to occur also in the middle portion of the shell 

 of Schwagerina as in Fasulina s. s. Such a case is seen in the 

 outermost whorl of Schwagerlna princeps, in a transverse section, 

 from east of Yang-chao-shan, Wei-nung-hsien, prov. Kwei-tschou 

 in China, as shown in fig. 1, })1. T. 



Fifthly, ' Sumatrina ' Annœ is said to possess, an extremely 



1) ScHELLWiEX : I.e., p. 258. 



