252 THE DEVONIAN OF MISSOURI. 



1913. Anoplotheca (Leptocoelia) flabellites Schuchert, Geol. Surv., Md. Low. Dev., p. 

 |£>7 438, pi. 73, figs. 29-33. 



tt^, Description — Shell of medium size, usually broader than long, from sub-oval to 

 semi-circular in outline. The pedicle valve of an average sized individual measures 

 11 mm. from beak to anterior margin, and 13 mm. along the hinge line which is equal 

 to the greatest width. 



Pedicle valve convex, the maximum convexity along the middle. Beak slightly 

 incurved above the hinge line, perforation in apex not observed. Cardinal extremities 

 rounded. Surface marked with ten coarse, angular plications, the middle plication 

 somewhat smaller than the two adjacent ones. 



"Dorsal valve flat; beak straight; hinge line sloping from the beak at an angle of 



110 to 160 degrees, rounded at the extremities On the dorsal valve the 



two middle plications are a little closer together, and slightly more prominent near the 

 front than the others; while the depressions separating them from these, each side, 

 are a little wider and deeper than those between the other plications."- — Hall, 1859. 



Remarks — This characteristic lower Devonian species is represented in the Little 

 Saline limestone by very few examples. There is a slight individual variation in the 

 shape, the degree of slope of the cardinal margins, and the amount of rounding of the 

 cardinal extremities, but on the whole the characters seem to be fairly constant. The 

 specimens observed are smaller than those of this species figured from the Grand Greve 

 limestone, and compare more closely in size with those from the Moose River sand- 

 stone, New Brunswick. 



Horizon — Lower beds. 



Figured specimens No. 27486, Walker Museum. 



MOLLUSCA 



Class PELECYPODA 



Order Prionodesmacea 

 Superfamily Pteriacea 

 Family Pteriidae 

 Genus Actinopteria Hall 



Actinopteria insignis Clarke 

 Plate 67, figures 1, 2 

 1900. Actinopteria insignis Clarke, Mem. N. Y. State. Mus., vol. 3, No. 3, pi. 35, pi. 4, 

 figs. 10-13. 



Description — Clarke discusses this species as follows: "In form and proportions 

 this shell resembles a young Actinopteria communis, but its habit is always small, and 

 its exterior profoundly cancellated. It is oblique, with large and much depressed 

 posterior wing, and small but nasute anterior wing, separated from the body of the shell 

 by a broad sulcus distinctly extending to the umbo. The principal radial striae are strong 

 and rounded, each interspace bearing from one to three very much smaller ones, making 

 a more marked contrast in the size of the radii than is exhibited by the species Actinop- 

 teria communis. These lines are crossed by close concentric lamellae cancellating the 

 entire surface, though both series of lines are quite obscure on the posterior wing. To 

 a certain degree this shell presents in miniature the characters of the species Actinopteria 

 textilis, which is mainly distinguished from its associate, Actinopteria communis, in the 

 stronger cancellation and interruption of the radii." — Clarke, 1900. 



Remarks — A single well-preserved small specimen referable to this species has been 

 observed and a larger one is doubtfully referred to the same species. 



Horizon — Lower beds. 



Figured specimens No. 27555, Walker Museum. 



