NO. 2297. BRACHIOPOD GENUS PLATYSTROFHIA—ilcEWAN. 435 



PLATYSTROPHIA CYPHA (James) 



Plate 47, figs. 22-25; plate 48, figs. 14-16. 



Delthyris lynx Hall, Pal. New York, vol. 1, pi. 32X>, figs. 1 E. S. T. U. 



Orthis (Platystrophia) cypha James, Cincinnati Quart. Jour. Sci., vol. 1, 1874, p. 

 20; not figured. 



Platystrophia cypha Cumings, Amer. Journ. Sci., ser. 4, vol. 15, 1903, p. 39, foot- 

 note. — FoERSTK, Amer. Geol., vol. 31, 1903, p. 341; Bull. Sci. Lab. Denison 

 Univ., vol. 16, 1910, p. 61, pi. 4, fig. lOa-6; pi. 5, fig. 11; pi. 4, fig. 12; Ohio 

 Naturalist, vol. 12, 1912, p. 453, pi. 22, fig. 5. 



Platystrophia lynx var. cypha Cumings, 32nd Ann. Rept. Dept. Geol. Nat. Res. 

 Indiana, 1908, p. 917. 



Mr. James described this species as a transverse gibbons form with 

 a hinge so long as to form spinelike projections; a profound sinus; a 

 remarkably elevated fold; convexity equaling the width across the 

 middle ; one strong plication in the sinus and an obscure rudimentary 

 one on each side; and tAventy-two to tv.enty-six angular costae on 

 each valve. 



Doctor Foerste saw the specimens preserved in the James collec- 

 tion ill the Walker Museum of Chicago University as types of Platy- 

 siropliia cyj^ha. Pie says: ^ 



The one numbered 2326 * * * is prolonged conspicuously along the hinge line; 

 it possesses 12 plications; on one side of the shell extend to about three-quarters of 

 an inch from the beak. The spinelike prolongation at the opposite end of the hinge 

 line has been broken off. The other specimens can not be regarded as types since in 

 these the prolongation of the shell along the hinge line does not exceed an eighth of 

 an inch and the number of plications on each side of the fold is 7 or 8 instead of 10 or 12. 

 Although all of these specimens can not be regarded as original types, they evidently 

 belong to the same species if my interpretation of the species is coirect. 



I have before me about 200 spechnens of this species, and those 

 which apply to this description are found at various horizons of the 

 Arnheini of Tennessee, Kentucky, Ohio, and Indiana. I have one 

 specimen from the iVi-nheim of Lebanon, Kentucky, which seems to 

 agree in flimensions with those which Mr. James took as his types. 

 It is 40 mm. along the hinge and 23.5 mm. wide a^^ross the middle. 

 There are 12 plications on the lateral slopes. This specimen, how- 

 ever, has four plications in the sinus and five on the fold. Individ- 

 uals of nearh^ every species of the triplicate group have been found 

 which have more than three plications in the sinus and four on the 

 fold, and this specimen represents one of these mutations. 



The average individual of these Arnheim forms has a hinge line 

 which is about one-fourth greater than the width across the middle, 

 and has 9 or 10 plications on the lateral slopes. The high com- 

 pressed fold has two strong and two weak plications; the profound 

 sinus has a strong median plication and two weak lateral plications. 



1 Bull. Sci. Lab. Denison Univ., vol. 16, 1910, p. 62. 



