250 SMITH. [Vol. XVI. 



Paranepionic. — Hyatt ^ says that the paranepionic substage 

 in the later ammonoids begins with the division of the ventral 

 lobe, and continues as long as only goniatite characters are 

 shown. In Schloenbachia oregonensis the sixth septum has a 

 divided ventral lobe and two lateral lobes, like GlypJiioceras (or 

 Goniatites s. str,). This is shown on PI. C, Fig. i. If we fol- 

 low Hyatt's definition the paranepionic stage will have to be 

 subdivided, for there are three well-marked goniatite stages in 

 it, the GlypJiioceras, Gastrioceras, and Paralegoceras stages. In 

 a recent paper ^ the writer has shown that GlypJiioceras in its 

 ontogeny goes through as a larva the stages Anarcestes and 

 Tornoceras {Parodoceras) ; as a youth it is a Prionoceras, and 

 takes on its own characters at a diameter of about 6 mm. 

 J. M. Clarke^ says that Tornoceras and Parodoceras are dis- 

 tinct genera, but that they appear along with Ariarcestes early 

 in the Devonian, and, therefore, are probably not descend- 

 ants from that genus, but have a common origin with it. If 

 this is the case the genealogy of the GlypJiioceratidae will have 

 to be revised, as will also the nomenclature of the chief genus 

 of the family, for E. Haug * has recently shown that Goniatites 

 de Haan must be retained for the group of G. spJiaericiis Martin, 

 while GlypJiioceras Hyatt may be retained for the group of 

 G. diadema. 



GlypJiioceras stage. — Now ScJiloenbacJtia oregonensis goes 

 through these same preliminary stages, but is so greatly accel- 

 erated that it reaches the glyphioceran stage at the end of the 

 first quarter of a coil from the protoconch, and at the sixth 

 septum, as shown on PL C, Fig. i. The early part of this 

 stage is shown on PI. A, Figs. 4 and 5, one-half coil, first eight 

 septa, and diameter 0.58 mm.; Fig. 6 shows a little more 

 advanced glyphioceran stage, development of the septa from 

 the third to the tenth, diameter 0.64 mm.; Figs. 7 and 8 show 



1 "Phylogeny of an Acquired Characteristic," p. 416. 



2 Proc. Calif. Acad. Sci., Series 3, vol. i; Geol., No. 3, 1897, " Development of 

 Glyphioceras," etc. 



3 " Naples Fauna (Fauna with G. Inhiviescens) in Western New York," ibth 

 Ann. Rep. State Geologist of New York, p. 109, 1898. 



* " fitudes sur les Goniatites," Mem. 18, Paleontologie, Soc. Ghl., France, 1898, 

 p. 27. 



