FERICYCLUS. 61 



greatest breadth, wliicli is just above the umbihcal slioulders. The surface 

 is ornamented by rounded furrows and anouhu- rid<:>-es that curve from the 

 unibiHcus gently backward toward tlie periphery, and tlien on the abdomen 

 bend sharply backward in a sinus. This ornamentation is characteristic of 

 Pcricydus, to which ofenus the species is assigned, although the septa have 

 not been seen. It is more evolute and less robust than P. princeps, but is 

 more nearl}' related to that tlian t(( any other known species. The strong 

 transverse ribs crossing the abdomen without interruption are not known 

 on any other genus of goniatites, and much reliance is jdaced in this char- 

 acter, even in the absence of knowledge of the septa. 



Occurrence. — Lower Carboniferous, Kinderhook stage, Sedalia, Mo. 



Pericyclus ? PRiNCEPS de Koninck. 



184:3. Goniatites princeps, L. G. de Kouinck. in crOmaliu.s. Precis elem. geol.. p. 515. 

 lS43-184:-±. Ammonites jM'incejys, L. G. de Koniiick, Dcscr. anim. foss., p. 579, PI. 



LI, figs. 2, 3. 

 1850. Agnnides princeps, A. d'Orbignv, Prod, de paleont. stratigr.. Vol. I, p. 116. 

 1852. Ammonites princeps, C. G. Giebel, Fauna der Vorwelt, Vol. Ill, p. 6-44. 



1880. Goniatites ijrincein^ L. G. de Koninck, Faune calc. carbon, de la Belgique, 



Vol. I, p. 268, PI. XLIX, tig-.s. 1, 2. 

 1882. Pericyclus princeps, E. von Mojsisovics, Cephalop. Mediterranen Trias- 

 provinz, p. 111. 



1881. Perici/clus princeps, A. Hyatt, Proc. Boston Soc. Nat. Hist., Vol. XXII, p. 330. 

 1888. Goniatite.s princeps, R. Etheridgc, British Fossils, Vol. I, Pahvozoic, p. 312. 

 1890. Glyphiocefras princeps, Steinmann and Doderlein, Elemente der Paliiont., p. 393. 

 1897. Pericyclus princeps, Foord and Crick, Catal. Foss. Ceph. Brit. Mas., Pt. Ill, 



p. 115, tigs. 68a and b. 



J. J. Bigsby " cites Goniatites princeps from the Goniatite limestone of 

 Rockford, Ind., Ijut no American collection is known to have an authentic 

 specimen of this, nor is it cited in any list of American species. In the 

 paleontologic collection of the Walker Museum, University of Chicago, is a 

 specimen wrongly labeled '■'■Goniatites princeps,''' ?a\({ this nia}" have been 

 the cause of the mistaken reference. Bigsby's citation is, therefore, prob- 

 ably a mistake. But it is by no means improbable that P. princeps may 

 be found in the Kinderhook of America, since P. hlairi, a closely related 

 form, shows that the genus Pericyclus is represented in America, and since 

 the rest of the Kinderhook fauna so closely resembles that of Ireland and 

 Belgium. 



« Thesaurus Devooico-Carboniferus, p. .3.36. 



