Permo-Carhoniferous Ammonoids of the Glass Mountains 69 



notched on its sides by the rudimentary adventive lobes. The other 

 part of the external saddle is much shorter and resembles the lateral 

 saddles in form. The lateral saddles are long, narrow' at the base, 

 broadening forward, rounded and often deeply notched on both sides 

 at the middle of their height. 



To this definition we can add that the internal suture (pi. I, fig. 49, 

 50) shows a deep bifid antisiphonal lobe occupying the whole breadth 

 of the dorsal part which corresponds in width to the venter of the 

 next smaller whorl. The internal saddle is very narrow and high. The 

 first and second lateral lobes are bifid, while the bottom of the five 

 auxiliary lobes is rounded. The lateral saddles are all high, entire 

 and rounded at the top. 



The internal suture of Medlicottia has been unknown up to the pre- 

 sent time; we shall show its outline on an immature specimen of M. 

 Burckhardti. According to what could be observed in some larger 

 specimens, the suture does not change essentially, with exception, per- 

 haps, of the number of auxiliary lobes. 



To the six species cited by Noetling another one Medlicottia Copei 

 White^ should be added; its suture resembles that of M. Orbignyana 

 more than any other. 



Medlicottia magnotuberculata Tchernow^ probably belongs to the 

 group of M. artiensis; at least the sculpture is very similar. Unfor- 

 tunately, the suture is not known. This group should certainly be 

 separated from Medlicottia and the species described by Gruenewaldt, 

 Karpinsky and Tchernow should be united in a new genus. 



Another species, Medlicottia (?) croatica, has been described by 

 Vogl.' 



To the species listed as belonging to Medlicottia we can add two 

 more from the Permo-Carboniferous of the Glass Mountains. One 

 has been found in the Leonard formation {M. Whitneyi) and the 

 other is frequent in the Word formation (M. Burckhardti) . Both are 

 entirely different from the other North American species, M. Copei; 

 and even belong to other groups. 



Noetling* contends that ( i ) in geologically older species the adven- 



•White, The Texan Permian, p. 21, pi. 1, fig. 1-3. 

 ^Tchernow, L'Btage d'Artinsk, p. 366, 397; pi. 1, fig. 7-a, b. 

 °D. V. Vogl, Palaeodyas von Mrzla-Vodica. 

 'Noetling, Medlicottia u. Episageceras, p. 354. 



