BRACHIOPODA. 409 



Triplecia ulrichi.l 



TRIPLECIA ULKICHI, n. sp. 



FIG. 31. Triplecia ulrichi, n. sp. a and 6, slightly restored dorsal and profile views of an entire 

 specimen; c and d, two views of the cardinal region of a dorsal valve, x 2; e, cardinal region of the ventral 

 valve, x 2, showing the area, apical perforation, and other features. Lower part of the Hudson River 

 shales, Fillmore county, Minnesota. Collection of E. O. Ulrich. 



T. ulrichi is distinguished from all other American forms of the genus, except 

 T. radiata Whitfield, in having rounded, rather distinct, radiating striae, of which 

 there are from thirteen to eighteen on each side of the fold and sinus, the median 

 region having seven or eight, making in all from thirty-three to forty-four on each 

 valve. The fold and sinus are well developed, but less than is usual with species of 

 Triplecia, and the deltidium is flat, never convex. All of the specimens seen are 

 more or less compressed, but the form in general seems to be near that of T. nucleus* 

 Hall. Interior characters as in T. extans-\ Emmons, sp., the type of Triplecia. 



The other American striated species of Triplecia is T. radiata% Whitfield from 

 the Calciferous horizon at Beekmantown, New York, differing from T. ulrichi in 

 being much smaller and less tumid. T. spiriferoides** McCoy, sp., of the Caradoc 

 sandstone of Wales, has a much longer cardinal line and a more sharply elevated 

 fold of the dorsal valve. 



The condition of the specimens of T. ulrichi may lead collectors to regard them 

 as species of Orthis near 0. borealis or coarsley striated specimens of 0. subcequata, 

 var. gibbosa, but the covered delthyrium of the ventral valve, or the tumid umbo of 

 the dorsal valve, will distinguish them from all orthoids. The forked cardinal pro- 

 cess is always broken in separated valves, appearing simple, but preparations from 

 specimens with the valves in place show it to have two delicate branches. 



Formation and locality. Ten specimens were found by Mr. E. O. Ulrich in the Hudson River group 

 at Wykoff and three miles north of Spring Valley, Minnesota. 



Genus LEPT^NA, Dalman. 



1828. Leptcena, DALMAN. Kongl. Svenska Vet.-Acad. Handl., for ar 1827, pp. 94-96, 106, 107 pi. I, figs. 1, 2. 

 1892. Leptcena, HALL. Paleontology of New York, vol. viii, pt. i, p. 276. 



In its relations this genus is nearest to Rafinesquina Hall, from which it differs 

 in its greater transversity ; more or less strongly corrugated and geniculated valves; 

 internal strongly elevated ridges near the outer margin of the dorsal valve, in which 



Pal. New York vol i, p. 138, pi. xxxin, figs. 2a-2c; 1847. 



tSee above report, p. 137, pi. xxxm, figs. la. Ib: 1847. 



JBull. American Mus. Nat. Hist., vol. 11, no. 2, p. 43, pi. VII, figs. 5-8; 1889. 



*Spe Pal. New York, vol. vlii, pt. i. p. 271. pi. xio. figs. 10, 11; 1892. 



