90 BRACHIOPODS. 



Cyrtina umbonata (HALL). 



Cyrtia umbonata Hall, .1858: Geology Iowa, vol. I, p. 512, pi. v, figs. 



2a-c. 

 Cyrtia missouriensis Swallow, 1860 : Trans. St. Louis Acad. Sci., vol. I, 



p. 647. 

 Cyrtina umbonata Miller, 1877 : Cat. Am. Pal. Foss. , p. 110. 



Similar to C. acutirostris, but more robust, with shorter 

 hinge-line and lower area. 



Horizon and localities. Devonian, Callaway limestone: 

 Callaway county ( Swallow ). 



Ambocoelia minuta WHITE. 



Amboccelia minuta White, 1862: Proc. Boston Soc. Nat. Hist., vol. IX, 

 p. 26. 



Shell very small, subcircular in outline, and marked by well- 

 defined lines of growth. 



Horizon and localities. Lower Carboniferous, Kinder- 

 hook beds : Hannibal. 



Athyris vittata HALL. 

 Plate xli, figs. la-b. 



Athyris vittata Hall, 1860: 13th Rep. N. Y. State Mus. Nat. Hist., p 89. 

 Spirigera minima, Swallow, 1830: Trans. St. Louis Acad. Sci., vol. I, 



p. 649. 

 Spirigera fultonensis Swallow, 1860: Trans. St. Louis Acad Sci., vol. I, 



p. 650- 

 Athyris vittata Hall, ]867: Pal. New York, vol. IV, p. 289, pi. xlvf, 



figs. 1-4. 



Shell very similar to A. argentea, but adult specimens are 

 much smaller, less ventricose, and the concentric laminations 

 much more pronounced. 



Horizon and localities Devonian, Callaway limestone : 

 Dauphin ( Callaway county ). 



Careful comparisons of a large series of good specimens 

 from Swallow's type locality seem to show conclusively that 

 Spirigera minima is merely the young of S. fultonensis. And 

 the latter appears to be, without the slightest shadow of doubt, 

 specifically identical with the common forms so widely distrib- 

 uted throughout the Mississippi basin in the Devonian rocks, 

 and so generally known under the name Athyris vittata of Hall. 



