BRACHIOPODA. 141 



Remarks — The specimens from southeastern Missouri average larger than specimens 

 C. mucronalus Hall and they have about twice as many plications, the common number 

 being 30 to 40. The pedicle valve is more strongly convex than in C. mucronalus Hall. 

 The character by which the species are differentiated at first sight is the much stronger 

 and fewer plications in C. mucronalus Hall. 



Occurrence — Common in the Beauvais sandstone of Little Saline Creek, Ste. Gene- 

 vieve County. 



Genus Productella Hall 



Productella spinulicosta Hall 



Plate 35, figures 10, 11 and 12 



Description and synonomy on pages 86 and 87 



Three specimens from the Grand Tower limestone of Little Saline Creek are in the 

 collections of Walker Museum. The specimens are small and incomplete but the 

 identification is fairly positive. Specimens of this species of about the same size have 

 been collected from the Mineola of Callaway County. 



Genus Strophalosia King 



Slrophalosia truncala (Hall) 



Plate 35, figures 1, 2, 3 and 4 



1843. Strophomena pustulosa Hall, Geol. New York, Rep. Fourth Dist., p. 181, fig. 4 

 1857. Productus truncatus Hall, Tenth Rep. N. Y. State Cab. Nat. Hist., p. 171. 

 1867. Productella truncata Hall, Pal. New York. IV, pp. 160-162, pi. 23, figs. 12-24. 

 1889. Productella {Strophalosia?) truncata Whiteaves, Cont. Canadian Pal. I, p. 112, 



pi. 16, figs. 1.2. 

 1897. Strophalosia truncata Schuchert, Bull. U. S. Geol. Surv., 87, p. 419. 

 1909. Strophalosia truncata Grabau and Shimer, North American Index Fossils, I, 



p. 240, fig. 292. 



1912. Strophalosia truncata Kindle, Bull. U. S. Geol. Surv., 508, p. 77, pi. 5, figs. 5-7. 



1913. Strophalosia truncata Prosser and Kindle, Maryland Geol. Surv., Middle and 

 Upper Devonian, pp. 160-162, pi. 13, figs. 14-16. 



Hall's description — "Shell small, concavo-convex; hinge line equalling or less than 

 the greatest width of the shell. 



Ventral valve gibbous in the middle, broadly truncate on the umbo, regularly 

 curving to the front, abruptly depressed at the sides, and forming narrow flattened ears 

 at the cardinal extremity. A narrow linear area, and a perceptible foramen or callosity 

 under the beak. 



Dorsal valve moderately concave, minutely truncate at the apex, with a thickening 

 of the hinge line in well-marked specimens. 



Surface of ventral valve wrinkled at the hinge line, marked by a greater or less 

 number of spiniferous ridges, supporting selnder spines of moderate length. There is 

 usually a row of two or three spines on the ears just below the hinge-margin, and they 

 are often closely arranged about the limits of the truncation on the umbo and more 

 sparsely on the middle and lower part of the valve. The dorsal valve is wrinkled along 

 the hinge line, and the surface covered by numerous elongate spiniferous pustules, 

 bearing, when perfect, long slender spines. The entire surface of both valves is marked 

 by fine closely arranged concentric striae. Interior of the dorsal valve wrinkled and 

 pustulose, with a conspicuous depression at the umbo, and a short bifurcating cardinal 

 process." 



Remarks — Fragments of S. truncata are not uncommon in the St. Laurent lime- 

 stone near St. Marys, Ste. Genevieve County. The parts preserved form a rather 



