50 CARBONIFEROUS AMMONOIDS OF AMERICA. 



No Permian forms are known that conld have developed out of this 

 genus, so probably it is the end of a series which itself is at present unknown, 

 for Pronorites could not have been the ancestor, and this is the only involute 

 discoidal member of the Prolecanitidse known from the Carboniferous. 

 This genus is the most highly specialized form known in the Carboniferous, 

 and is as complex as any yet described from the Permian. The occurrence 

 of such forms suggests the great gaps that exist in our knowledge of the 

 Paleozoic ammonoids, and inspires the hope that eventually these gaps will 

 be filled out. 



Occurrence. — Schuchertites is at present known only from tlie Upper 

 Coal Measures, the type of the genus, Schuchertites (/rahami sp. nov., being 

 known from only a single locality, Graham, Tex. Named in honor of Mr. 

 Charles Schuchert, of the U. S. National Museum. 



SCHUCHEKTITES GRAHAMI Smith, sp. UOV. 



PI. XXI, fig.s. 20-22. 



This species, represented by only a single imperfect specimen, IT. S. 

 Nat. Mus. No. 27206, is laterallv compressed, discoidal, involute, with flat- 

 tened sides, narrow umbilicus, and narrow channeled abdomen. Surface so 

 far as known is devoid of ribs and constrictions, but has fine curved cross 

 stria? of growth, forming gentle undulations on the shell. 



The septa are complex and ammonitic, divided into eight lol)es and 

 saddles. The siphonal lobe is divided by a short angular secondary saddle; 

 the first five lateral lobes are undivided and digitate, and there are three 

 simple auxiliary lobes, not digitate, but club-shaped. The first lateral 

 saddle is divided by a short rounded secondary lobe, the other lateral 

 saddles are undivided, and rounded at the extremities. The lobes are 

 sharply constricted at the upper portion, giving a club shape to the lobes 

 and a phylliform appearance to the saddles. The septa, instead of running 

 in a straight line across tlie sides, are arranged in a backward-])ointing 

 curve, parallel to the stria? of growth. Internal septa unknown. 



Occurrence. — Upper Coal Measures, Graham, Young County, Tex., 

 about a thousand feet below the Permian, associated with a typical Upper 

 Coal Measures fauna. Collected by A. B. Gant. 



