PLA1M^ XV. 



(All tij.'ures mi tliis plate are twenty timeti enlarged, except tig. 9, which is twice natural pize.) 



Page. 



GoNI ATITES CKENISTKIA PhlUipS 68 



Figs. 1, 2. Adolescent stage, IJ whorls, diameter of 1.29 mm., last whorl is ananeanic 

 { I'rlonocem.t stage) and shows transition from paranepionic. 

 Fig. 1. Front. 

 Fig. 2. Side. 

 Figs. :i, 4. Adolescent stagt-, ilianieter of 1.37 mm., IJ whorls, Prliiitorerns stage. 

 Fig. 3. From front. 

 Fig. 4. From side. 

 Figs -1, H. .Adolescent stage, diameter nf l.tU nmi., 2S whorls, Primioniit.i .otagc. 

 Fig. 5. From front. 

 Fig. (i. From side. 

 Figs. 7, 8. End of adolescent stage, diameter of 2.2.5 mm. ; 2J whorls; transition from Pria- 

 liocems to (iiniintili'x in the division of the ventral lobe, and beginning ronmling of the 

 whorl. 



Fig. 7. From front. 

 Fig. 8. From side. 

 Fig. 9. ]<;arly adult stage, diamettr of 1.5 nun. 

 NoTK. — This was PL XIV, Proc. Cal. Acad. Sci., 3d series. Geology, Vol. I. All specimens figured 

 on this plate came from the Lower Carboniferous, St. Louis-Chester stage, Moorefield, Ark. 



178 



