Permo-Carboniferous Ammonoids of the Glass Mountains 119 



saddle is very broad, low, asymmetrical, much steeper on the inner 

 flank than on the outer one. In the larger specimens the lobes are 

 slightly pointed and the auxiliary saddle is a little higher 



The internal lobes (pi. VI, fig. 46) are very simple. They consist of 

 a deep funnel-shaped, antisiphonal lobp, a very similar but shallow 

 first lateral one, a triang-ular internal saddle, and a very broad and low 

 lateral saddle. Between this and the first auxiliary external saddle 

 there must exist a broad but shallow lobe with its deepest point im- 

 mediately upon the umbilical seam; but it could not be observed di- 

 rectly. The internal lobes do not change materially in the larger 

 specimens. 



Dimensions :^ 



I II III 



Diameter 14.8 mm (1) 14.4 mm (1) 14.3 mm (1) 



Width ?12.3 mm 0.84 11.1mm 0.77 11.1mm 0.78 



Height of last whorl 9.2 mm 0.62 8.0 mm 0.56 8.0 mm 0.56 



Diameter of umbilicus... 1.0 mm 0.068 ?1.0 mm 0.069 1.0 mm 0.07 



IV V VI 



Diameter 11.8 mm (1) 11.6 mm (1) 10.5 mm (1) 



Width 9.1 mm 0.77 9.1 mm 0.78 8.6 mm 0.82 



Height of last whorl ... . 6.8 mm 0.58 6.1 mm 0.53 5.8 mm 0.55 



Diameter of umbilicus. . ? 0.8 mm 0.069 ?0.7 mm 0.067 



VII VIII IX 



Diameter 8.3 mm (1) 8.0 mm (1) 7.5 mm (1) 



Width...- 7.0 mm 0.84 7.1mm 0.89 ?6.2 mm 0.83 



Height of last whorl.... 4.5 mm 0.54 4.5 mm 0.56 4.3 mm 0.57 



Diameter of umbilicus. . ? 0.5 mm 0.063 0.4 mm 0.053 



X 



Diameter 6.4 mm (1) 



Width 5.6 mm 0.88 



Height of last whorl.... 3.1 mm 0.48 



Diameter of umbilicus... 0.3 mm 0.047 



Relation to other species: 



The nearest relative of our form is probably Agathiceras Frechi n. 

 sp., but it is easily distinguished by its finer spiral ribs, and less sub- 

 globose form and the narrower umbilicus. 



'There are still larger specimens at the aame localities, but no specimen could 

 be found well enough preserved to show the exact dimensions. One of these speci- 

 mens was at least 28 to 30 mm. in diameter; it shows that the height of the last 

 whorl is only a little less than the width. The measurements of the umbilicus in 

 the table above are not quite ptact with the exception of the first one. 



