Permo-Carboniferous Ammonoids of the Glass Mountains 203 



three branches to the ventral and three others to the umbiHcal side. 

 In medium-sized specimens only the upper side branch is phylloid, but 

 the two next ones show at least an inclination to a phylloid termina- 

 tion, while the lower ones rather seem to be somewhat pointed. The 

 first lateral saddle is entirely analogous in its form to the external 

 saddle, being only a little lower and narrower. Also the following 

 saddles seem to have a similar form to the first ones. 



In one specimen part of the internal suture could be observed. We 

 see there the characteristic deep and slender anti-siphonal lobe and 

 the extremely high and slender internal saddle which ends in an ob- 

 lique phyllum, the first lateral lobe is similar to the anti-siphonal one 

 but less deep and quite asymmetrical. These internal lobes and saddles 

 correspond in their construction entirely to those of the type of the 

 genus Perrinites vidriensis, described in another part of this paper. 



Our species is similar to that occurring in the Wichita, found by 

 Wrather and described above. It is perhaps a little stouter and more 

 globular, certainly much more involute. The ventral part is flatter 

 in our species. Much greater is the difl^erence in the suture. In our 

 species the siphonal saddle has two long branches on each side, while 

 in the other species it has only a narrow shelf -above the base. Sim- 

 ilarly, the external and the first lateral saddle of our species show a 

 greater number of side branches. Very different is the form of the 

 siphonal lobe, each branch of which in the older form is much shorter 

 and stouter, and also much more asymmetrical than in the species de- 

 scribed here. The other saddles are similar to those of the older form 

 but more ramified. 



Similar differences we find between this species and Perrinites Cum- 

 minsi White, the lobes and saddles of our species being in general more 

 ramified than those of the older form; another distinguishing feature 

 is that the saddles of our species are much higher and the lobes much 

 deeper and more slender than in P. Cumminsi. 



On the other hand, if we compare our species with specimens of 

 higher forms, as P. HUH Smith, P. compressus, and P. vidriensis, we 

 find that the suture of our species is very much simpler, the ramifica- 

 tions of the saddles and lobes in those younger forms being much 

 more numerous and varied than in the specimens from Runnels County. 

 Especially different is the form of the siphonal saddle and the first 



