Permo-Carboniferous Ammonoids of the Glass Mountains 193 



Agathiceras sp. ind. 



In our collection is a fragment' belonging to Agathiceras which is 

 sufficiently preserved for a description. 



Shell very involute, slightly flattened on the flanks, especially toward 

 the umbilicus, strongly rounded on the venter. Cross-section of the 

 whorl elliptical, broader than high. Umbilicus very narrow, umbilical 

 wall apparently rather deep, umbilical border rounded. Flanks flat- 

 tened on the third nearest to the umbilicus, the rest being well rounded 

 and curving continuously toward the venter. Greatest width near the 

 umbilical border. 



Ornamentation on the mold consists of fine and sharp spiral ribs, 

 about 20 to 22 between the sipho and the umbilical border, separated 

 from each other by shallow, wide furrows with rounded bottom, much 

 wider than the ribs. 



Septa rather well separated, never touching each other. Suture 

 very simple, following a line slightly curved forward, and consisting 

 between the sipho and the umbilical border of four lobes, with a fifth 

 on the umbilical border, and four saddles. 



The external lobe is very broad and divided into two branches by a 

 high median saddle; each of these branches is wider than the first 

 lateral lobe, slightly pointed at the base, below the middle a Httle wider 

 than at the mouth. The median saddle is high, slender, and in the 

 middle rather well constricted. The first lateral lobe is a little deeper 

 than the branches of the siphonal lobe, it is symmetrical, slightly 

 pointed at the bottom, wider in its lower third than at the mouth. 

 The second lateral lobe is very similar in form to the first one, but a 

 little shallower and perhaps also narrower. The first auxihary lobe is 

 asymmetrical, its flank nearest to the venter being convex while the 

 flank toward the umbilicus is concave. The second auxiliary lobe on 

 the umbilical border is apparently funnel-shaped, but not entirely 



visible. 



The external saddle is very high and slender, higher than the median 

 saddle and also a little higher than the first lateral saddle, strongly 

 constricted at the base, club-shaped at the upper end. The first 

 lateral saddle is very similar to the external one but lower and nar- 

 rower. The second lateral saddle is asymmetrical, its flank nearest to 

 the venter is concave, the flank nearer to the umbilicus is convex; the 



