BRACHIOPODS. 91 



Athyris hannibalensis (SWALLOW). 



Plate xli, flg. 9. 



Spirigera hannibalensis Swallow, 1860: Trans. St. Louis Aead. Sci., 

 vol. I, p. 649. 



A rather large, lenticular form, with distant, concentric, im- 

 bricated lines of growth. 



Horizon and localities. Lower Carboniferous, Louisiana 

 { Kinderhook ) limestone : Hannibal, Louisiana, Sulphur Springs 

 ( Saint Louis county ). 



Athyris proutii (SWALLOW). 



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

 649. 



Eesembling A. vittata, but with mesial fold more pro- 

 nounced. 



Horizon and localities. Lower Carboniferous, Louisiana, 

 (Kinderhook) limestone: Hannibal, Louisiana, Clarksville 

 (Pike county ), Sulphur Springs ( Saint Louis county ). 



Athyris incrassatus HALL. 



Plate xli, fig 10. 



Athyris incrassatus Hall, 1858: Geology Iowa, vol. I, p. 600, pi. xii, 

 fig. 6. 



Shell very large, heavy, flattened, with occasional imbri- 

 cated lines of growth; surface otherwise smooth. 



Horizon and localities Lower Carboniferous, Burlington 

 limestone : Hannibal, 



Athyris formosa (SWALLOW). 



Spirigera formosa Swallow, 1863: Trans. St. Louis Acad. Sci., vol. II, 



p. 91. 

 Spirigera euzona Swallow, 1863: Trans. St. Louis Acad. Sci., vol. II. p. 91. 



A small form resembling closely A. trinuclea. 

 Horizon and localities. Lower Carboniferous, Keokuk 

 limestone : Boonville ( Cooper county ). 



