A CARBONIFEROUS BRACHIOPOD 66 1 



diameter/ In C. granulifer the youngest form obtainable has the 

 spines on the extreme outer edge of the hinge-line. 



As mentioned under the description of the Specific Characters in 

 the incipient form of this shell, there is a deep pit or sinus just in 

 front of the beak on the ventral side, and a corresponding convexity 

 just in front of the hinge-line on the dorsal side. This would be an 

 indication of an early species with these characters and also the two 

 preceding. This form is found in the species Chonetes lepidus from 

 the Marcellus shale^ which represents the probable type of shell from 

 which C. granulifer is descended. 



The figure,^ which is a ventral view, shows a deep sinus and in the 

 description, it is stated that the dorsal side follows the curves of the 

 ventral. It will be noted that C. lepidus is a striated species, while the 

 nepionic stage of C. granulifer is glabrous. This has little bearing, 

 as it is a general characteristic of the incipient shells of brachiopods 

 to be glabrous. 



Ephihic stage. — ^Following the laws of development, we could 

 assume the great bulk of adults of C. granulifer in the upper Car- 

 boniferous of Kansas and below the Florena members of the Garrison 

 formation to be like the ephibic stage in the Florena — Grand Summit 

 series, and upon investigation, this proves to be the case, while above 

 and below these limits, they should be more like the gerontic and late 

 neanic stages respectively. This holds true in nearly every instance. 



As was stated in the introduction, the type specimens probably 

 came from a horizon between the Topeka and Tecumseh limestones. 

 Specimens from these horizons correspond with the typical ephibic 

 form, so that the type specimens represent just about the normal 

 form of the species. 



We find Norwood and Pratten's species, C. smithii,'^ that of Meek 

 and Worthen,^ and that of Hall and Clark^ to be a short-eared form 



I Raymond, The Developmental Change in Some Common Devonian Brachiopods, 

 Vol. XVII, pp. 277-300. Pis. XII-XVIII. 



a Hall, Pal. N. Y., IV, Pt. i, pp. 132 and 142, PI. XXII, Fig. 12. 



3 Ibid. 



4 Norwood and Pratten, Jour. Acad. Nat. Set. Phil. (2), Vol. Ill, p. 24, PI. II, 

 Figs. 2a-c. 



s Meek and Worthen, Geol. Surv. Illinois, Vol. V, 1873, p. 570, PI. XXV, Fig. 11. 

 6 Hall and Clark, Pal. N. Y., VIII, Pt. i, 1892, XV B, Fig. 12. 



