Permo-Carhoniferous Ammonoids of the Glass Mountains 133 



Relation to other species: 



There does not seem to be any other species known which could be 

 compared to ours. The only one which resembles it somewhat is St. 

 glohosum Gemm./ but this differs by its less globose form. A nearer 

 comparison cannot be made because the suture of the Sicilian species 

 has not been figured and that of ours is only imperfectly known. 



Age: 



Word formation, Permo-Carboniferous. 



Number of specimens examined: 

 Two. 



Locality: 



Junction of Road and Gilliam Canyons, Glass Mountains. 



Marathonites nov. subgen. 

 Type : Marathonites J. P. Smithi Bose 



When we contemplate the species which have been united under the 

 name of Stacheoceras we observe that most of the Sicilian species have 

 a very great number of lobes between the sipho and the umbilicus. 

 They vary from six {St. perspectivum) to ten (St. mediterraneum, St. 

 Gaudryi). Only the St. pygmaeum shows not more than five, but this 

 species is a very small one and may even be composed of younger in- 

 dividuals of other species. On the contrary, the species from the Rus- 

 sian Artinsk in general have not very many lobes with the exception 

 of St. Kingianum and St. Lahuseni, which also distinguish themselves 

 from all the rest by their outer form. Of St. sp. ind. (cf. Parkeri 

 Heilpr. ) we do not know how many lobes exist, but St. Romanowskyi 

 shows only four (5) lobes and St. Krasnopolskyi six (7) lobes. 



Similar conditions we find in the Stacheoceras described from the 

 Pennsylvanian of North America. Stacheoceras Parkeri Heilpr. has 

 only four lobes, the last of which is on the umbilical shoulder. St. 

 Ganti J. P. Smith has five lobes. 



In our lowermost strata of the Permo-Carboniferdus the genus 

 Stacheoceras is represented by five species, while a sixth one has been 



•Gemmellaro, Calc. c. Fusullna, p. 31, pi. 4, fig. 13, 14. 



