Permo-Carboniferous Ammonoids of the Glass Mountains 185 



cal, but not nearly as deep as the first lateral lobe and not half as wide. 

 It is divided into two parts by a small saddle at its base. The branch 

 nearer to the umbilicus Es2 of the external saddle is simply tongue- 

 shaped and in its form similar to the following lateral saddles but much 

 smaller and rather resembling one of the rudimentary saddles of Esi. 

 The two lateral saddles are high, slender, narrow, tongue-shaped, ana 

 in the lower half slightly constricted. The auxiliary saddles, at least 

 six in number, are much shorter than the lateral ones, and decrease 

 slowly in height toward the umbilicus ; the first two are still similar in 

 form to the lateral saddles, while the next ones are triangular and 

 rounded. A seventh and very low auxiliary saddle exists on the um- 

 bilical border; apparently there follows another one on the umbilical 

 wall. 



This species is represented by seven specimens. 



The similarity between this species and M. artiensis Gruenew. is 

 rather surprising. In both species we find the strongly beaded keels, 

 although those of M. artiensis are much broader in adult individuals, 

 while those of our species resemble more the keels of the younger 

 specimens of M. artiensis, as figured by Karpinsky.^ The ribs on the 

 flanks observed by this author do riot seem to exist in our species. 

 The sutures are very similar, especially on account of the low and 

 broad ventral branch Esi of the external saddle, with only two rudi- 

 mentary lobes on the umbilical flank. M. artiensis has two rudi- 

 mentary lobes on the ventral flank of Esi, while our species has only 

 one. The adventive lobe "A" is also very similar in both species,^ as 

 well as the form of the first two lateral saddles and lobes. In both 

 species the difference in depth between the first and second auxiliary 

 lobes is very great, and a quite characteristic feature. The 

 form of the lateral and auxiliary saddles and lobes is in both species 

 practically the same. The main difiference between M. artiensis and 

 our form may be found in the siphonal lobe and the external saddle, 

 the former being much deeper in the Russian species and the latter 

 somtewhat broader, but these differences are only specific, while the 

 general character of both forms shows that they belong to the same 

 group. 



' 'Karpinsky, Amm. d. Artinsk. PI. I, flg. 1 c, 1 d. 

 "Especially flg. I-l, pi. I of Karpinsky, while later on A does not seem to be bifid. 



