(52 CARBONIFEROUS AND PERMIAN FORAMINIFERA. 



Interior labyrinthic, or having the chamber cavities subdivided by irregular, ramifying 

 septa. Texture arenaceous, rough externally. Aperture irregular, compound, or dendritic. 



It will be seen by the above brief summary of characters that the term (Lituola} is 

 here employed very much in the restricted sense in which it is used by German 

 systematists ; that is, to the exclusion of the adherent Lituoline forms (Placopsilina 

 d'Orb.), the uniserial, non-convoluted varieties (Reophax, Montfort), and those with non- 

 labyrinthic chamber cavities (Haplophragmium, Reuss), all of which hitherto have usually 

 been included in the genus by English authors. On a previous page an outline of the 

 general scheme of classification of Foraminifera propounded by Professor Reuss was 

 given, and this may properly be supplemented by his views on the arrangement of the 

 group " Lituolidea " as elaborated in his latest work, together with his preliminary 

 remarks thereupon. The summary of which the following is a translation will be found 

 in the second part of " Das Elbthalgebirge in Sachsen," p. 119, a memoir published in 

 1874, that is the year following the lamented death of its author. 



" 1. LITUOLIDEA." 



" Test free or attached, either entirely spiral or spiral in the earlier and rectilinear in 

 the later portions, or else having the chambers strung together in a single, almost 

 straight, or crooked line. The chambers often nearly regular, with simple undivided 

 cavity, or sometimes having the interior subdivided by very irregular, shelly ingrowths. 

 Aperture simple or compound, externally cribriform, perforated. 



" The English investigators of the Foraminifera place together almost all the Lituo- 

 line forms under the genus Lituola, which thereby is endowed with a very wide range. I 

 prefer, even on palaeontological grounds, notwithstanding an undeniably close relation- 

 ship to arrange them in a larger number of groups. This result is brought about in the 

 following scheme :" 



1 . Test adherent : Poli/phrayma, Reuss. 



2. Test free. 



A. Chamber cavities simple, not subdivided : Haplophragmium, Reuss. 



a. Entirely spiral, orifice crescentic, situated on the inner margin of the 



terminal chamber adjoining the previous convolution. (Nonionine 



forms.) 

 I, Test with spiral commencement, later chambers in straight series, crozier- 



shaped ; aperture simple or compound, terminal. (Spiroline forms.) 

 c. Test completely spiral. Aperture rounded or elliptical, approximately 



in the middle of the convex septal plane. (Orbignyina, von Hagenow.) 



B. Chamber cavities subdivided by irregular, ramifying septa, cellular. 



a. Test spiral at the commencement afterwards straight, crozier-shaped ; 

 mouth dendritic, labyrinthic or compound. Lituola, Lamarck. 



