Trlpleola ulrlchi.l 
BRACHIOPODA. 
409 
Triplegia ulkichi, n. sp. 
Fig. 3t. Triplecia ulrichi, n. sp. a and b, 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. extansf Emmons, sp., the type of Triplecia. 
The other American striated species of Triplecia is T. radiataX 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. horealls 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. Lepta:na, Dalman. Kongl. Svenska Vet. -Acad. Handl., for ar 1827, pp. 94-96, 106, 107 pi. r, figs. 1, 2. 
1892. Leptmna, Hall. Palajontology of New York, vol. viii, pt. i, p. 276. 
In its relations this genus is nearest to Rufinesquina Hall, from which it difters 
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. xxxm, figs. 2a-2c; 1847. 
+ See above report, p. 137, pi. xxxiii, figs. la. lb: 1847. 
*BuU. American Mus. Nat. Hist., vol. li, no. 2, p. 43, pi. vu, flgs. 5-8: 1889. 
**See Pal. New York, vol. viii, pt. i, p. 271, pi, xic, figs. 10, 11; 1892. 
