140 CARBONIFEROUS AMMONOIDS OF AMERICA. 



The species seems to have reached a diameter of at least 50 mm., but 

 only fragments of the larger ones have been found. The nearest known 

 relative is Waagenoceras stachei Geramellaro, from the Permian Fusulina 

 limestone of Sicily. 



Occurrence and localitij — Permian, Wichita stage, military crossing of 

 the Big Wichita River, Baylor County, Tex. 



Waagenoceras hilli Smith, sp. nov. 

 PL XXVII. 



Tliis species is more compressed laterally than Waaffenoceras cumminsi 

 White, has narrower umbilicus, and higher whorl, but the whorls are less 

 deeply embracing-, the involution being less than one-half of the height of 

 the whorl. There are five sinuous constrictions on the last revolution, 

 which bend sharply backward on the abdomen. The surface is otherwise 

 smooth, so far as can be ascertained from the casts. 



The septa are much more complex than on W. cumminsi at the same 

 size, the lobes and saddles are all deeply divided; the saddles are phylli- 

 form, with three leaf-like divisions; the lobes are digitate, with three prin- 

 cipal finger-like extensions, resembling the septa of Pliylloceras, and being 

 more complex than those of any other species yet known of Waagenoceras. 

 There are seven lobes visible outside of the umbilicus, the ventral, five 

 laterals, and one on the umbilical shoulder, being one less than is seen on 

 the species described by Gemmellaro" from the Permian of Sicily. The 

 agreement with that genus is not perfect, but the Texas species is nearer 

 to that than to any other, and the differences are hardly sufficient for the 

 discrimination even of a subgenus. 



Dimrnslons of the Jiijured specimen. 



Millimeters. 



Diameter 98 



Height of last whorl 53 



Height of last whorl from the preceding .31 



Width of last whorl 48 



Involution 22 



Width of umbilic'u.s 10 



This specimen was septate throughout, so the length of the body 

 chamber, and the full size of the shell could not be determined; but in the 



"Fauna calc. Fusulina, pp. 9-12. 



