WAVEELY GROUP SPECIES. 285 



Prof. Swallow's types of his Spirigera Hannibalensis, but believe it to be 

 the same form described by him. In regard to its relations to Athyris 

 lamellosa, I can only say that a comparison of our specimens with Mr. 

 Davidson's figures of that species shows no constant diflerences, though 

 it varies much in form, and while some specimens agree quite nearly 

 with A. lamellosa, others seem to have a shorter and more obtuse ventral 

 beak than those figured by Mr. Davidson. It should also be explained 

 here that the specimen represented by our figure on plate 14 is rather 

 more than usually transverse, and has a longer and straighter hinge 

 than the others. The latter character, however, is more marked than 

 natural, in consequence of the fact that the specimen is merely an in- 

 ternal cast, the thick shell of the rostral region, when present, causing 

 the hinge margin to appear shorter. 



This shell seems also to be nearly related to Athyris crassicardinalis, 

 White, described from near the same horizon at Burlington, Iowa, and 

 may be the same. I regret having no opportunity to make the neces- 

 sary comparisons with Prof. Swallow's and Dr. White's types, to be able 

 to arrive at more satisfactory conclusions in regard to their relations to 

 the form under consideration. I had expected to do this before preparing 

 the description, and had also intended to give here much more full and 

 complete illustrations of this and the other Waverly Brachiopoda, but, as 

 elsewhere explained, a failure of health rendered this impossible, and 

 made it necessary merely to arrangie on the plates such of the figures as 

 were already drawn at the time they were called for. 



Locality and position: Sciotoville, Ohio. In the Waverly group of the Lower Car- 

 boniferous. 



Genus 8PIRIFER, Sowerby, 1815. 

 (Min. Conch., II., 42.) 



Spieifer Caeteei, Hall. 



Plate 14, figs. 7a, 6, c, (d1) 



Spirifer Carted, Hall (1857) ; Regents' 10th Ann. Eept. on State Cak Nat. Hist. N. Y., 

 170. 



Spirifer {Cyrtiaf) Hannibalensis, Swallow (1860) ; Trans. St. Louis Acad. Sci., I., 647. 



Compare Spirifer texivs, Hall (1857) ; Eegents' 10th State Cab. N. H. Report, 169 : also 

 Spirifer capax, Hall (1858) ; Iowa Geological Eeport, p. 520, pi. 7, figs. 7a, b: Syrin- 

 gothyris typus and S. HaM, Winchell (1863) ; Proceed. Acad. Nat. Sci., Philad., pp. 7 

 and 8 : and Spirifer euspidatus, Martin (sp.), as illustrated in Mr. Davidson's Monogr. 

 Brit. Garb. Brach., pis. 8 and 9. 



Shell attaining a rather large size, very thin, nearly semicircular, as 

 seen in a direct view from above or below, and rhombic-subquadrangular 

 in a front or posterior view, with length generally a little more than half 



