100 THE DEVONIAN OF MISSOURI. 



Remarks— Swallow's S. annae and S. amarus are, without question, the same. 

 Specimens are abundant in some places and the differences displayed are in size, number 

 of plications, and height of cardinal area. All have the radiating striae and the varia- 

 tions in other respects are not striking. The resemblance in shape to Cyrtina triquetra 

 Hall which occur with Spirifer annae is so close that in most cases one must look for the 

 striae to distinguish them. 



Occurrence — Snyder Creek shale of Montgomery and Callaway Counties. 



Spirifer asper Hall 



Plate 19, figures 19-23; plate 23, figure 4. 



1858. Spirifer aspera Hall, Geol. Survey Iowa, I, pt. 2, pp. 508-509, pi. 4, fig. 7. 

 1882. Spirifer {Cyrtina) aspera Whitfield, Geol. Wisconsin, IV, p. 331-332, pi. 26, 



figs. 1, 2. 

 1894. Spirifer "asper Hall and Clarke, Pal. New York, VIII, pt. 2, pp. 29, 31, 32, 39, 



pi. 25, figs. 20-25. 

 1897. Spirifer asper Schuchert, Bull. U. S. Geol. Survey, 87, p. 382. 

 1909. Spirifer asper Grabau and Shinier, North American Index Fossils, I, p. 331. 

 1909. Spirifer asper Greger, Am. Jour. Sci., XXVII, p. 377. 



1911. Spirifer asper Cleland, Wis. Geol. and Nat. Hist. Surv., Bull. 21, pp. 76-77, pi. 

 16, figs. 1-5. 



Hall's description — "Shell semielliptical, width about twice the length; hingeline 

 equaling the greatest width of the shell, and abruptly angular at the extremities. 

 Ventral valve triangular pyramidal, extremely elevated at the umbo, and sloping 

 abruptly to the lateral and anterior margins; mesial sinus shallow, strongly defined 

 at its margins, equal or less in height than the length of the valve, transversely and 

 vertically striate; foramen proportionally narrow, extending to the beak, and partially 

 closed within by a pseudo-deltidium; beak not incurved. Dorsal valve nearly flat or 

 moderately convex; mesial fold strongly defined at the margins, and rounded above. 



Surface, in full-grown specimens, marked by twenty or more simple rounded and 

 moderately elevated plications on each side of the mesial fold and sinus. Plications 

 often fifteen to eighteen in ordinary specimens, four or five only of which reach the 

 beak, the others running out along the hingeline and margins of the area; concentrically 

 marked by fine imbricating lines of growth, which are sometimes very conspicuous. 

 Entire surface granulose; granules closely arranged, sometimes visibly following the 

 concentric striae, and in other parts apparently scattered without order." 



Remarks — Specimens from Missouri are not as large as average specimens from 

 Iowa and the number of plications on either side of the fold and sinus is usually 15 or 

 16 rather than more than 20. 



Occurrence — Rare in Snyder Creek shale and Callaway limestone of Callaway 

 County. 



Spirifer euryteines Owen 



Plate 22, figures 1-12; plate 23, figures 2 and 3 



1844. Delthyris euruteines Owen, Rep. Geol. Expl. Iowa, Wis. and 111., p. 69, pi. 12, 



• fig- 9. 

 1852. Spirifer euruteines Owen, Geol. Survey, Wisconsin, Iowa and Minnesota, p. 



586, pi. 3, figs. 2-6. 

 1858. Spirifer parryanus Hall, Geol. Survey Iowa, I, pt. 2, p. 509, pi. 4, fig. 8. 

 1858. Spirifer capax Hall, Geol. Survey Iowa, I, pt. 2, pp. 520-521, pi. 7, fig. 7. 

 1861. Spirifera Parryana Billings, Canadian Jour., VI, p. 261, figs. 77, 78. 

 1863. Spirifera Parryana Billings, Geol. Canada, p. 386 : fig. 422. 

 1868. Spirifer fornacula Meek and Worthen (non Hall), Geol. Survey Illinois, III, 

 p. 433, pi. 13, fig. 8. 



