Permo-Carboniferous Ammonoids of the Glass Mountains 199 



to the second lateral saddle, only a little lower. The second lat- 

 eral saddle is high, slender, nearly symmetrical, with slight lateral 

 swellings on both sides, but at different heights, which causes an in- 

 dication of trilobate form. The first auxiliary saddle is very similar 

 to the first one and nearly as high. The ten auxiliary saddles visible 

 on the flank are much shorter than the two lateral ones and decrease 

 in height toward the umbilicus. The first three are similar in form to 

 the lateral saddles, while the rest have a tongue-shaped form. 



This species is quite commpn at the locality; in our collection it is 

 represented by more tha;i a dozen specimens. 



Both our Medlicottia belong to the same group, notwithstanding 

 the exceptional form of the first lateral lobe in one of them. They 

 have a certain relationship with M. Copei White, although they are 

 specifically distinct. While our forms have sharp keels those of the 

 older species are slightly beaded. The suture is also somewhat distinct 

 although the ground plan is similar. The main differences are the 

 greater number of rudimentary saddles and lobes, and of auxiliary 

 saddles and lobes in the individuals from Runnels County, notwith- 

 standing that the specimen figured by White is larger than most of 

 those from Runnels County. There are still more differences in the 

 details, as for example, the greater width of the first lateral saddle in 

 the species from the old Military Crossing; the non-existence of a real 

 secondary saddle in the adventive lobe "A" and the rounded bottom of 

 the lowest rudimentary lobe on the umbilical flank of Esi in White's 

 species. Nevertheless, both our species and M. Copei belong certainly 

 to the same group of Medlicottia or at least to groups not very distinct. 

 We must not forget that beaded keels' are often found in the smaller 

 whorls of species which have distinctly sharp keels in the larger ones 

 {M. Whitneyi n. sp., M. Orhignyana Vern.). The nearest relative of 

 our species, and belonging certainly to the same group, is M. Orhign- 

 yana Vern.^ The similarity in the general form of the lobes is cer- 

 tainly surprising; we see the same general development of the external 

 saddle and the lateral and auxiliary ones even down to details, as are 

 the forms of the rudimentary lobes both on the umbilical and on the 

 ventral flank of the branch Esi, the form of the adventive lobe, the two 

 laterals, etc. There is also the distinguishing feature of the sudden 



'Karpinsky, Amm. d. Artinsk, p. 32, pi. 11, fig. 1. 



