Permo-Carhoniferous Ammonoids of the Glass Mountains t 35 



there is no possibility of actually proving that they belong also to our 

 new subgenus. 



Marathonites shows the following characters : 



Shell discoidal, of rather globose form, generally not much flattened 

 on the flanks, with semilunar transversal section, very involute. Um- 

 bilicus small and deep. Whorls deeply embracing and slowly growing. 

 Length of body chamber unknown. The surface is ornamented with 

 fine transversal striae slightly curved toward the back. The whorls 

 show transversal constrictions on the mould, corresponding to inter- 

 nal varices ; these show generally a slight sinuosity open towards the 

 forepart. These constrictions show also on the surface of the shell. 



The sutural line (pi. VI, fig. 79, 80) consists of nine lobes and ten 

 saddles between the umbilical shoulders (the entire external surface), 

 one lobe on the umbilical wall, nine lobes and eight saddles on the in- 

 ternal side, while another saddle is on the umbilical seam; so that the 

 whole suture consists of twenty lobes and twenty saddles. The suture 

 forms always a nearly straight line and curves only very little toward 

 the forepart. The siphonal lobe is broad, divided into two branches by 

 a high saddle, somewhat constricted in the middle. Each of the two 

 branches of the antisiphonal lobe is bifid, the interior point being some- 

 what longer than the exterior on the umbilical side. The antisiphonal 

 lobe is divided into three parts by two relatively high and slender 

 saddles, the middle branch being much deeper than the two lateral 

 ones. 



All the rest of the lobes are either trifid or bifid on the external side 

 as well as on the internal. All the saddles are high, slender, rounded, 

 entire, slightly constricted near the base. The median saddle of the 

 siphonal lobe is notched by a shallow indentation. 



Marathonites J. P. Smithi nov. sp. 

 PI. VI, Fig. 77-89 



Shell of subglobose form with rounded flanks, very involute, slightly 

 compressed on the flanks and broadly rounded on the external side. 

 The greatest breadth is a little .above the umbilical border. The spire 

 is formed by a great number of slowly-growing whorls much broader 

 than high. The whorl curves slightly down toward the umbilical 

 border, forming a very steep but narrow umbilical wall between the 



