P'ermo-Carboniferous Ammonoids of the Glass Mountains 139 



Number of specimens examined: 



Fourteen. The species is quite common at the locality. 

 Locality: 



Immediately northwest of Wolf Camp, Glass Mountains. 



Marathonites sulcatus n. sp. 

 PI. VII, Fig. 1-4 



Shell of subglobose form, slightly flattened on the flanks, rounded on 

 the ventral side, very involute; the greatest breadth is very httlc 

 above the umbilical shoulder. The spire is formed by a great num- 

 ber of slowly growing whorls which are much broader than high. The 

 flank curves slightly down to the umbilical border, the umbilical wall 

 being very steep but narrow. The umbilicus itself is extremely narrow 

 and very deep. On the last whorl of the cast four deep transversal 

 constrictions are visible. They are slightly bent backward and on the 

 ventral part show a broad curve open (concave) toward the forepart. 

 The body chamber is not preserved. Our specimen being a cast, no 

 ornamentation could be observed. 



The sutural line (pi. VII, fig. 4) is nearly straight, only bent a very 

 little backward in the siphonal region. The septa are very close and 

 even touch each other on the flank of the inner part of the whorl. All 

 the saddles are entire, high, relatively broad, rounded at the top, and 

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

 branches by a median saddle. Each of the branches is bifid, the inner 

 point being much longer than the outer one. The first and second lat- 

 eral and the first auxiliary lobes are trifid, the middle point being very 

 little longer than the two lateral ones, which in the first and second 

 lateral lobe are of about equal length. The first auxiliary lobe is decid- 

 edly asymmetrical, the middle point being longer than the internal lat- 

 eral one, and this one much longer than the external one. The second 

 auxiliary lobe is apparently bifid but could not be well observed. The 

 first lateral lobe is much narrower than the siphonal one, but broader 

 than each of the branches ; the second lateral lobe is a little narrower 

 and much shallower than the first one, while the first auxiliary is 

 broader than the second lateral but much shallower, although its 

 points reach as deep down as those of the first lateral. The median sad- 

 dle of the siphonal lobe is high and slender; it is slightly notched at 



