44 



ing line to an acute point, which is slightly anterior to the first 

 acute point, wbere it makes another sharp retral angle and again 

 curves forward in a waving line to a level with the anterior part 

 of the first saddle and then abruptly curves back a short distance 

 and then forward and back, so as to make the summit of the sad- 

 dle bifid, and to form a short, narrow lobe at the periphery in 

 the middle of the ventral side. There are, therefore, two sad- 

 dles upon each side of the bifid saddle, as the periphery of 

 the volution. It will be noticed that the septum above described 

 is very much like the septa in G. illinoisensis, and distinguished 

 by having shorter saddles, which are less constricted in the middle 

 part. The sinuosities and shape of the septa in the two species 

 will be best understood by comparing the illustrations. 



This species will be distinguished from O. illinoisensis by the 

 proportionately large umbilicus, shorter dorso-veutral diameter, less 

 gibbous volutions, which are more abruptly rounded from the 

 umbilicus, and by the form of the septa. It is probably more 

 nearly related to that species than to any other which has been 

 described. 



Found by W. J. Parrish in the Upper Coal Measures at Kansas 

 City, Missouri, and now in the collection of AVm. F. E. Gurley. 



GONIATITES GREENCA8TLENSI8, n. Sp. 



Fldle r, Fig. 12, lateral view; Fig, 13, ventral view. Fig, 14, 

 surface form of a septum. 



Species medium size, globose, volutions expanding laterally quite 

 rapidly and broadly rounded from umbilicus to umbilicus. The 

 number of volutions not known. Transverse section of a volution 

 concavo-convex and the transverse diameter, where our shell is 

 broken off, is more than four times as much as the dorso-ventral. 

 The transverse diameter proportionately diminishes toward the 

 apex and increases toward the body chamber. The last volution 

 embraces all the inner ones and leaves a large open umbilicus 

 that is like a hollow cone and formed by the beveling of each 

 outer volution from the inner volution to the margin of the um- 

 bilicus. The shell on the interior of the umbilicus is concen- 

 trically lined and furrowed. The shell is depressed convex from 

 the margin of one umbilicus to the margiu of the other, leaving 

 no lateral sides and the greatest transverse diameter at the margin 

 of the umbilicus. The surface of the shell is finely cancellated. 

 The air chambers are rather long. 



Each septum is arched backward from the umbilicus to a rather 

 rx'ute point where it makes a retral angle and curves forward and 

 back in the form of half an ellipse (but not extending quite as 



