Permo-Carboniferous Ammonoids of the Glass Mountains igy 



umbilicus. The exact number of auxiliary saddles cannot be observed 

 but is certainly great. 



Only two specimens of this form have been found at the locality. 

 As the species is very similar to the next one, we shall defer a discus- 

 sion of its relationships until we have described Medlicottia n. sp. II. 



Medlicottia n. sp. II. 



^ Shell discoidal, very involute, flanks very little curved, nearly flat 

 in the portion near the umbilicus, venter truncated and provided with 

 a deep and wide furrow, limited on both sides by a sharp keel. Cross- 

 section of the whorl sagittiform, much higher than broad, greatest 

 width in the middle, truncated at the ventral part and notched there 

 by the furrow. The inner half of the flank near the umbilicus is 

 almost flat, while the outer one is rather regularly curved toward the 

 ventral keel. The borders of the venter are form;ed by sharp keels 

 which do not show any tubercles or beads. The spiral furrow on the 

 venter is wide and deep. The umbilicus is very narrow, the umbilical 

 wall seems to be narrow and steep, the umbilical border is rounded. 

 All the specimens are casts and do not show any ornamentation. 



The suture is that of a typical Medlicottia. Between the sipho and 

 the umbiUcus it follows a curved line. A very characteristic feature 

 of it is that the auxiliary lobes are considerably shallower than the 

 two lateral ones and the first auxiliary. The septa stand very near 

 together, the points of the saddles touching the base of those of the 

 next younger line. The following description refers to a specimen 

 with a whorl about 30 mm. high. 



The external lobe is clearly bifid, but the form of the siphonal saddle 

 could not be entirely recognized; the lobe is moderately deep, and 

 reaches down to the base of the secondary saddle, which divides the 

 adventive lobe "A" in two parts. The first lateral lobe is bifid and 

 asymmetrically oblique, the branch nearest to the venter being con- 

 siderably longer and stouter and much more curved than the one lying 

 toward the umbilicus ; it is shallower than the second lateral lobe. The 

 second lateral lobe is deeper than all the rest of the lobes, bifid, the 

 branch nearer to the venter being a little deeper than the one nearer to 

 the umbilicus. The first auxihary lobe is similar to the second lateral 

 one although a little shallower but the branch nearer to the venter is 



