40 



longed point, in line with the two preceding acute points, where 

 it again takes a retral course and extends forward as far as the 

 second prolonged curve, and instead of arching over the middle 

 of the periphery, abruptly curves back a short distance and then 

 forward and back so as to leave the summit of this saddle bifid, 

 and to form a short narrow lobe in the middle of the ventral 

 side. There are, therefore, seven saddles and seven lobes without 

 including the small narrow lobe in the middle of the ventral side. 

 The three saddles on each side rapidly increase in length from 

 the umbilicus toward the periphery, and the one on the periphery 

 has a length about equal to the middle one on each lateral side. 

 The numerous sinuosities of the septa are best understood by ob- 

 serving the illustrations. When we look at an end view of a 

 volution or at the face of a chamber, we see, not only the seven 

 projecting saddles, the middle one of which is bifid, as above de- 

 scribed, but also two short ones on each side at the mouth of the 

 umbilicus, one of which is indicated by the gentle arch which 

 turns over the margin above mentioned, and the other is within 

 the mouth of the umbilicus and forms the inner angle of the 

 truncated horn of the subcrescantiform chamber, and precedes the 

 angle first above mentioned. This inner saddle is not disclosed, 

 in a coiled shell, but the one on the margin of each umbilicus 

 might very well be counted, making nine saddles in a septa. 

 The siph uncle is rather large, and as usual, near the dorsal side 



This species will be distinguished by its general form, the great 

 number of sinuosities in the septa, and by the nine exposed sad- 

 dles in each septum. 



Found by John Wolf, in the Coal Measures, in Fulton county, 

 Illinois, and now in the collection of W^m. F. E. Gurley. 



GONIATITES KENTDCKIENSIS, S. A. Miller. 



Plate V, Fir/. I, lateral view of a large specimen preserving the 



Older shell. 



This species was described and illustrated in North American 

 Geology and Palaeontology, page 439, from the inner whorls of 

 specimens, that did not preserve any of the outer shell. The 

 volutions are unusually numerous in this species, though the 

 number in a mature shell is still unknown. Evidently there are 

 ten or more. In a large shell two or three of the volutions may 

 be seen by looking into the umbilicus, but in the younger speci- 



