G. H. Girty — Triticites. 



235 



ing wall. Let, however, the outer wall be removed by weath- 

 ering or by artificial means, and the surface is seen to be very 

 regularly divided into rhombs, which the eye naturally follows 

 in spiral rows. 



In the form from the Mississippi Y alley for which the name 

 Triticites is proposed, the partitions are for the most part 

 straight, and not fluted except in the immediate vicinity of the 

 axis, so that the greater portion of each chamber is not divided 

 into chamberlets. There is also a slight formal difference 

 between Triticites and Fusulina, since the former seems not 

 to occur in the elongate subcylindrical shapes often found in 

 the latter. Triticites is usually subglobose or spindle-shaped, 

 but as Fusulina likewise develops these forms, configuration 

 is of but limited importance in discriminating the two genera. 



Transverse section. 

 xlO. 



Longitudinal section. 

 xlO. 



Externally they will many times look almost precisely alike, 

 except for the aperture, which, if exposed, will at once serve 

 to distinguish them. In weathered specimens the long almost 

 parallel lines of the partitions in Triticites are in marked con- 

 trast to the reticulation formed by these structures in Fusulina. 

 Transverse sections in the two genera are sometimes nearly 

 alike. In each case a spiral wall is seen from which in Triti- 

 cites simple projections extend at regular intervals toward the 

 center, reaching in some cases nearly, and in others com- 

 pletely, to the preceding volution. This is well shown by fig. 

 1, which represents Triticites secalicus. A transverse section 

 through Fusulina presents a similar appearance, save that the 

 partition walls are frequently represented by looped or forked 

 lines, instead of by simple ones. The radial walls are seen in 

 many cases to be incomplete, and it is probably by means of 

 the apertures thus left that communication between succeed- 

 ing chambers was maintained. In longitudinal section the 

 difference is more apparent. The concentric walls of Fusu- 

 lina enclose between them lines, sometimes straight, sometimes 

 curved, often loop-shaped, which are the edges of the inter- 



