PKOLECANITES. 55 



1879. Oon!af!Us h/<,)n, J. Hull, Tal. N. Y., Vol. V. Pt. 11. p. 47t;, I'l. LXXII. %. 12; 



PI. LX'XIII. Hu-s. '.1-11: Pi, LXXIV, %. 7. 

 1882. Prolccanifiv h/iml., E. \<>ii Mojsisovic.s, Cephtilop. MeditcrruiuMi Trias|)i'oviiiz. 



p. 199. 

 1888. Goniatites /yo?u\C. L. Hcnick. P.ull. Deiiisoii Univ.. Vol. 1\'. PI. VII. tig. 2. 

 18it.5. OoniatUes lyoni, C. L. Ilcrrick, Geol. Surv. Ohio. Vol. VII. PI. XVIIl, tig. 2. 

 lS9'.t. Prolecanltcxh/oii!. F. Frccb. Die Stein Ivohlenformation, PI. XLVI, .1, tig. 11. 

 1901. Pi'dlrcdiiitin li/<iiii. F. Freeh. LTeber devonisehe Aminoneeii. p. 64-, fig. 21 c. 



Shell discoidal, compre.ssed, evolute; whorLs liiit Utile einhracing, only 

 about one-liftli of the inner volutions being- covered by the outer ones. 

 Whorls six or more in number, tlie inner ones being semielliptical in cross 

 section and the outer ones trapezoidal, with flattened sides and abdomen 

 and rounded shoulders. Breadth of the whorl is two thirds of the heisrht. 

 The whorls enlarge very slowly, giving a large number of whorls for a 

 small diameter. 



Length of body chamber unknown, but fragments indicate that speci- 

 mens have attained a diameter of 80 or HO mm., exclusive of body chandler. 



Surface of the shell unknown, but the cast is smooth and devoid of 

 constrictions and all other surface ornamentation. 



Septa lanceolate, with pointed and slightly muci'onate lobes and rounded 

 saddles. Ventral lobe undivided and shorter than the laterals, which are 

 two in numljer; the dorsal (internal) lobes consist of an undivided tongue- 

 shaped antisiphonal, with ji, short, blunt lobe on the umbilical margin. The 

 total number of lobes is therefore one pair less than on most species 

 of Prolecanites, l)ut this difference has not been considered by any writers 

 to be of generic value, since so many otherwise typical species of Proleca- 

 nites possess this number of lobes, and several even have one more pair 

 than the normal. 



Occurrence. — Prolecanites li/oni occurs in the Lower Carlioniferous, 

 Kinderhook stage, at Rockford, Ind., along with Aganhles rotatorius de 

 Koninck, Muensteroccras oweni Hall, M. paraUelum Hall, Prodromites prrema- 

 turus Smith and Weller, and P. fjorhyi Miller. It has also been found in the 

 same horizon in the Waverly group of Granville, Ohio. 



Prolecanites marshallensis Winchell. 



1862. Goniatites iiKirs/i'i/lcnstti, A. Winchell, Am. Jour. Sci.. 2d serie.s. Vol. XXXIII, 



p. 362. 

 1865. GoniatttesmarshaUcmisi, A. Winchell. Proc. Acad. Nat. Sei. Phila., 186,o,p. 133. 

 1870. Goniatttes mi(r!<li<iJh'n><i.s, A. Winchell. Proc. Am. Philos. Soc, Vol. XI. p. 258. 



