Permo-Carboniferous Ammonoids of the Glass Mountains 171 



26 does not belong to that genus^) . In the Glass Mountains the genus 

 is represented by only one species, W. Dieneri n. sp., but this one is 

 exceedingly common at most of the localities where the horizon occurs. 

 It is found in the lower mass of limestone of the Word formation, 

 ^ where it occurs in greater numbers than most other species. 



The nature of the rock does not allow of breaking the specimens up 

 and studying the suture on the interior whorls. It has therefore not 

 been possible to show if this genus has any ontogenetic relation to 

 Perrinites, which always occurs in beds far below the Waagenoceras 

 limestone. 



Waagenoceras Dieneri nov. sp. 



PI. X, fig. 28-31; PI. XI, fig. 1-27 



Shell subglobose, involute, slightly flattened on the flanks, well 

 rounded on the venter, whorls very deeply embracing and slowly 

 growing. Cross-section semilunar, much broader than high. Um- 

 bilicus narrow and deep with a rather sharp umbilical shoulder; the 

 umbilical wall is broad and nearly perpendicular. The involution is 

 nearly four-fifths of the height of the whorl in the larger specimens, 

 and about four-sevenths in the interior whorls. The casts of the 

 inner whorls generally thow about four deep constrictions which past 

 •over the whole whorl in a practically straight line without having 

 any inflection on the venter; these contrictions correspond to internal 

 varices of tlie shell. On the larger whorls these constrictions grow 

 more shallow and even seem to disappear entirely. The surface of 

 the shell is not known but does not seem to have possessed any very 

 strong ornamentation. The body chamber is unknown. 



The septa are rather near together and in some places almost touch 

 each other. The suture (pi. X, fig. 31; pi. XI, fig. 3, 5, 6, 10) fol- 

 lows a strongly curved line between the sipho and the umbilicus. The 

 suture consists of the siphonal lobe, seven lateral and auxiliary lobes, 

 and seven saddles between the sipho and the umbilical shoulder ; there 

 are one saddle and one lobe more on the umbilical wall. 



'When the manuscript of this paper was already finished, I had the opportunity 

 to look through a number of fossils collected by Mr. Ch. L. Baker in the west side 

 of the Delaware Mountains at a point north of the Apache Mountains, West Texas. 

 This collection contains not only several specimens of typical Waagenoceras but also 

 generically different forms which seem to correspond to Girty's "Waagenoceras" 

 Cumminsi var. Ouadalupensis. 



