Permo-Carboniferous Ammonoids of the Glass Mountains 149 



Vidrioceras Uddeni nov. sp. 

 PI. VII, Fig. 40-61 



Shell globose in the younger stages, with somewhat flattened flanks 

 and flattened ventral portion. In the larger specimens both these 

 parts are more rounded; very involute in the later stages, but much 

 less so in the inner whorls. The greatest width is a little above the 

 umbilical border. This latter one is not sharp but slightly rounded; 

 the umbilical wall is vertical but not very broad. The umbilicus 

 is narrow and very deep in the larger whorls and rather broad in the 

 younger stages. The height of the whorls increases somewhat with 

 the advancing age, but in general the whorls grow very slowly and 

 are deeply embracing. On each whorl we count two to three deep 

 constrictions (on the cast) strongly curved toward the front re- 

 gion. The body chamber is unknown. 



In none of our specimens is the shell preserved, but on the cast 

 we often observe the trace of an ornamentation which consists of very 

 low transversal undulations, bent slightly backward near the um- 

 bilicus, but curving energetically toward the front part on the flanks 

 and especially in the ventral region. The broad ribs are separated by 

 much narrower interstices. The same kind of ornamentation shows 

 on the inner side of one of the whorls, the ribs being generally paral- 

 lel to the constrictions mentioned above. 



The sutural line (pi. VII, fig. 43, 47, 60, 61) is nearly straight with 

 only a slight inflection backward in the siphonal and antisiphonal re- 

 gions. The septa are not very near each other. All the saddles are 

 entire, high, slender, and rounded at the top. The siphonal lobe is 

 divided in two branches by a high and slender median saddle. Each 

 of the branches is asymmetrical and ends in one point which lies en- 

 tirely on the inner side of the branch. The first lateral lobe is nearly 

 symmetrical and bifid; it is not much broader than each of the 

 branches of the siphonal lobe. The second lateral lobe is also practi- 

 cally symmetrical, but ends in only one point and is a little broader and 

 deeper than the first one. The first auxiliary lobe is similar in shape 

 to the first lateral and also bifid ; it is in its upper part wider than the 

 second lateral, which is in that part much narrower than in the middle. 

 The second auxiliary lobe is very shallow and funnel-shaped. The 

 third auxiliary lobe, which lies on the umbilical wall, is relatively 



