144 University of Texas Bulletin 



Stacheoceras Ganti^ Smith is a much more involute form and St. 

 Parkeri Heilprin^ has an entirely different suture, the first lateral lobe 

 being bifid, instead of trifid, as in our species. 



With respect to Stacheoceras Romanowskyi Karp. and St. 

 pygmaeum Gemm., we could only repeat what we have said about them 

 in our paragraph on M. J. P. Smithi n. sp., adding solely that the ex- 

 ternal form of the Sicilian species is entirely different from that of our 

 species. 



Age: 



M. vidriensis has only been found in the Wolf Camp division, the 

 lowest Permo-Carboniferous. 



Number of specimens examined: 



Nine. The species is quite frequent at the locality. 



Locality: 



Immediately northwest of Wolf Camp, Glass Mountains. 



f Marathonites Hargisi nov. sp. 

 PI. VII, Fig. 33-39 



Shell globose, with rounded flanks and ventral portion; involute, 

 with the greatest width at the umbilical border. The spire is formed 

 by a great number of very slowly growing whorls which are much_ 

 broader than high. The umbilicus is relatively narrow and deep, its 

 border is very sharp, its wall is broad and vertical. On the last whorls 

 three deep transversal constrictions are visible ; they are slightly bent 

 backward, in the flanks a little more than on the ventral portion. The 

 body chamber is unknown. No ornamentation is visible on the cast. 



The septa are not very near together and nowhere touch each other. 

 The sutural line (pi. VII, fig. 36, 39) is practically straight with a 

 slight inflection in the siphonal region. All the saddles are entire, high, 

 relatively broad, rounded at the top, and the first three are slightly 

 constricted near their base. The siphonal lobe is divided in two 

 branches by a high median saddle. Each of the branches is bifid and 



'Smith, Carb. Amm. of America, p. 132, pi. 21, flg. 14-16. 

 'Heilprin, Proc. Acad. Nat. Sci. Phila., 1884, p. 53, flg. 1, 2. 



