60 CARBONIFEROUS AMMONOIDS OF AMERICA. 



lateral lobe, twice as long as the veutral, clavate and pointed, and a short 

 triangular auxiliaiy lobe on the umbilical shoulder. The external saddle 

 is long and broadly rounded, the lateral saddle is narrower and shorter. 



This species is said to be most nearly related to '' Goniatites'' allci Win- 

 chell, but differs in its shorter and rounded ventral lobe, its longer lateral, 

 and in possessing the auxiliar)" lobe; also its sides are less convex, and the 

 umbilicus less abrupt than in (t. allei. 



Occurrence. — Lower Carboniferous, Kinderhook stage. Lower Waverly 

 group, Newai-k, Ohio. 



Grenus Pericyclus Mojsisovics. 



Goniatites princeps de Koninck was chosen by E. von Mojsisovics as 

 the type of the genus Pericyclus, characterized by its angular lobes, s})atu- 

 late saddles, and coarse ribs crossing the abdomen. Hyatt " included this 

 under his family Glyphioceratidaj, on account of a supposed transition from 

 Brancoceras to Pericyclus. In a later paper Hyatt'' places Pericyclus in a 

 new family, Pericyclidse, supposed to differ from the Cllyphioceratidtie in 

 the possession of two internal lateral lobes instead of one on each side. 

 This was based on Hang's mistaken copy of the septa of Pericyclus kochi 

 Holzapfel," in which there seem to be two internal laterals. A figure of the 

 septa of this species is given by Holzapfel, ^ show;ing but one internal lat- 

 eral lobe on each side. There can, therefore, be no reason for separating 

 this genus from the GlyphioceratidEe. 



Pericyclus blairi Miller and Gurley. 



PI. XVI, figs. 4, 5. 



1896. GoniatUes hJairi, Miller and Gurley, Bull. Illinois State Mus. Nat. Hist. 

 No. 11, p. 35, PI. IV, %s. 4, .5. 



Shell discoidal, moderately evolute, becoming more so with age; 

 whorls compressed, with rounded venter and flattened sides, with subangu- 

 iar umbilical shoidders. Umbilicus narrow in youth, but widening rapidly 

 with age as the spiral opens out, on account of the fact that the whorl 

 increases very slowly in height. Height of whorl slightly greater than its 



cProc. Boston See. Nat. Hist., Vol. XXII, p. S.30. 



iCophalopoda, p. 551, in Eastman's Transl. Zittel's Elements of Palasontology, 1900. 



f Etudes sur les Goniatites, p. 27, fig. 6c. 



tfPal.Abhandl., Vol. V, PI. Ill, tig. 6. 



