Permo-Carboniferous Ammonoids of the Glass Mountains 79 



one, but broader and slightly constricted near the base. The first aux- 

 iliary saddle is similar to the lateral ones, and still slightly constricted 

 at the base, although a little less long; while the following three aux- 

 iliary saddles decrease gradually in length and are not constricted. 

 A fifth auxiliary saddle probably exists on the umbilical seaiTi. 



Dimensions: 



Most of the specimens found are only fragments, especially the 

 larger ones. Dimensions can be given, therefore, only for smaller 

 individuals; but there are fragments which show that the complete 

 shell would have a diameter of at least 130 to 140 milHmeters. This 

 proves it to be the largest species of Medlicottia so far found, the 

 largest fragments of M. primas indicating a diameter of about 120 mm. 

 Dimensions: I n m 



Diameter ? 55.0 mm (1) 19.1 mm .(1) 



Width 26.8 mm 11.4 0.21 4.7 0.25 



Height of the last whorl . . 76.0 32.0 0.58 11.2 0.59 



Diameter of umbilicus Small Small ... 1.5 0.07 



Relation to other species : 



M. Burckhardti has certain affinities with M. Verneuili Gemm.^ 

 This refers only to the suture, because our species does not show any 

 of the shallow grooves on the flank nor any of the transversal folds 

 that are characteristic for the Sicilian species ; but we have to consider 

 that our species is only known by casts and that a faint sculpture 

 is not always preserved on these. The general character of the suture 

 is very similar in both species, although the Sicilian species has a 

 smaller number of auxiliary lobes. Extremely characteristic is the 

 shape of the external saddle and especially the form and position of 

 its umbilical branch, Es2, and the deep adventive lobe A, but in general 

 the lateral and auxiliary saddles are higher and more slender in M. 

 Burckhardti than in M. Verneuili and the secondary saddles which 

 divide the lobes in two branches are shorter. 



Much more diflferent is M. primas Waag.,^ although it has the tri- 

 lobate saddles. The shape of the external saddle is entirely dififerent 

 and the lateral saddles are more strongly trilobate and lower. 



'Gemmellaro, Calc. c. Fusulina, p. 48, pi. 5, fig. 4-8; pi. 8, fig. 5 (Not 26, as is 

 said in Gemmellaro's text). 



'Waagen, Productus limestone fossils, I, p. 39, pi. 2, fig. 7. 



