Permo-Carhoniferous Ammonoids of the Glass Mountains 191 



Flanks flattened on the third nearest to the umbiHcal border, on the 

 upper two-thirds the flanks pass into the venter in a continuous curve. 

 Umbilicus very narrow and deep with a distinct though somewhat 

 rounded border ; umbilical wall very steep, nearly vertical. 



Cast smooth, shell ornamented by extremely numerous and fine 

 transversal lines, which on the .flank in the region near the umbilical 

 border are bent backward while on the upper part of the flank they are 

 curved forward and on the venter slightly curved backward, the con- 

 cavity being on the front side. 



Septa rather well separated from each other, never touching each 

 other. Suture very simple, following a slightly curved line between 

 the sipho and the umbilical border, and consisting there of five lobes 

 and four saddles, a fifth lying on the umbilical border. 



The siphonal lobe is extraordinarily wide and is divided into two 

 branches by a median saddle. The median saddle is high, slender, 

 of the form of the upper part of a bottle, broader at the base than at 

 the upper end, with slightly concave flanks. Each of the two branches 

 of the siphonal lobe is much narrower than the first lateral lobe ; each 

 branch is asymmetrically bifid, the longer point lying nearer to the 

 sipho ; in its middle part the branch is wider than at the mouth. The 

 first lateral lobe is much wider and a little shallower than the branches 

 of the siphonal lobe ; it is distinctly trifid, the central point being con- 

 siderably longer than the lateral ones; in its lower half the lobe is a 

 little wider than at the mouth. The second lateral lobe is extremely 

 similar to the first in its form, equally symmetrically trifid, the middle 

 point being much longer than the lateral ones ; the lobe is a little 

 shallower and narrower than the first and the flanks are only very 

 slightly concave. The first auxiliary lobe is wide, triangular, funnel- 

 shaped, ending in a sharp point; at the mouth it is as wide as the 

 second lateral lobe. The second auxiliary lobe is similar to the first, 

 but rounded at the base, with straight flanks, of triangular form, very 

 wide at the mouth. 



The external saddle is very high and broad, tongue-shaped rather 

 than club-shaped, only very slightly constricted in the middle. The 

 first lateral saddle is sim|ilar in form to the external one but much 

 lower, narrower, and not constricted. The second lateral saddle is 

 slightly asymmetrical, the flank nearer to the umbilicus being less 



