•T^* '"^ *sC3 



Permo-Carboniferous Ammonoids of the Glass Mountains 57 



the preceding one, and also much narrower and not constricted; the 

 second auxihary saddle, which is on the umbilical wall, is an insignifi- 

 cant saddle. 



The suture described above is visible still near the point where the 

 furrow on the ventral region begins. From here on, the suture begins 

 to change materially. The secondary saddle in the first lateral lobe 

 develops a slight bulge on its inner side and so becomes asymmetrical ; 

 at the same time the number of auxiliary saddles and lobes on the 

 flank near the umbilical region increases rapidly and constantly. The 

 umbilical portion of the secondary saddle in the first -lateral lobe then 

 begins to grow much quicker than the siphonal one. At about the 

 fourth part of a whorl from the point where the furrow begins, this 

 secondary saddle becomes still farther subdivided. Its siphonal por- 

 tion, which has developed into an independent secondary saddle, shows 

 a slight notch which divides it into two equal parts, while the umbilical 

 portion of the original secondary saddle has grown so far that it can 

 almost be considered as an independent lateral saddle. If we still con- 

 sider this saddle as a secondary one, we count in this part eight saddles 

 and eight lateral and auxiliary lobes. This is apparently the final 

 stage of development. In the largest whorl there is only one more 

 change, insofar as the notch on the siphonal part of the secondary 

 saddle -deepens so much as to cause two little secondary saddles, the 

 umbilical one of which is a little higher than the siphonal one. 



Before continuing, I shall try to describe the final stage of the suture 

 in our genus. The evolution of the suture proves that the highest 

 saddle has to be considered as the first lateral one, and that all the pro- 

 tuberances between it and the external saddle must be regarded as se- 

 condary saddles of the broad first lateral lobe. In the final stage, the 

 siphonal lobe is extremely narrow and deep. It occupies only the 

 width of the furrow on the ventral part. It is narrower at its upper 

 part than below the middle, and its bottom is divided into three branches 

 by two lateral, relatively long and pointed, saddles which lean over 

 towards the sipho. The middle branch does not seem to be closed 

 and is much longer than the lateral branches. The first lateral lobe lies 

 on the ventral shoulder, is extremely broad, and is divided into four 

 branches by three secondary saddles. The deepest of these branches 

 is the outer one (counting always the part toward the sipho as the 



