2 ART. 5. — H. YABE : 



outgrowths of the wall ; they are usually shorter, and always 

 without a median lamella/^ which is invariably present in the 

 2:)riinary septa. Tlie transverse septa (the ' Nebensepten ' of C^ 

 Schwagek) are those at right angles to the other two, extending 

 from the roof of a volution to its floor, when completely de- 

 veloped. When only the basal portion of the transverse septa is 

 developed, they appear as spiral ridges, and form what are general- 

 ly called the basal skeleton (* Basalskelet '). Although all the 

 septa, like the wall itself, are often perforate throughout their 

 entire length, yet it frequently happens that they are imperforate 

 iu their lower portion which then appears as a quite dense cal- 

 careous mass. The basal skeleton is also never perforated, the 

 pores being evidently not physiologically necessary."^ 



Synopsis of the Four Subgenera. 



1. FUSULINA s. s. Type: F. cijlindrica Fischer. 

 Shell fusiform or cylindrical, sometimes ellij^soidal, rarely 



acicular. Only the primary septa developed ; these are much 

 folded, especially near the umbilical ends. 



2. SCHWAGERINA. Type: S. jmnceps Ehrexberg. 

 (cfr. PL ir., fig. 1). 



Shell sj^therical in the typical species, fusiform in those ap- 

 proaching Fusulina s. s. With only the primary septa, which are 

 slightly or not at all folded, except near the umbilical ends. 



1) Tlie term in;iy be iiKippmpi iate ; but T inenn by it :i boiindiiry line between two 

 successive walls, wiiicli simietiinos luii.s into llie nilddle >.>( tlie tepla. See the remarks by 

 ScHELi.wiKN on the structure of" the septa. 



2) I ajjfree with Schei^mvien in the view tlial tlie greater traiisi)arency of the wall and 

 of the upper i)art of the sc|)ta is due to the intercalation of commonly transparent calcite, 

 iiifdtrated in the pores; otherwise we have no reason to maintain the greater turbidity of 

 the deu!-e cilcareous matter in the basal portion of the septa. 



