FOSSILS OF THE DEVONIAN. 143 
Spirifera (M.) undifera Roemer. 
Plate iii, figs. 3, 3 a, b, 6, 6-a; plate xiv, figs. 11, 11 a, b. 
Spirifer undiferus Roemer, 1844. Rhein. Uebergangseb., p. 70 u. 73, tab. iv, figs. 5, 6. 
undiferus Schnur, 1853. Dunker’s Paleontographica, vol. ili, Brach., Hifel., 
p. 204, tab. xxxiv, figs. 3 a-d. 
Sandberger, 1855. Brach., Rhein, Schichtensystems, p. 18, pl. xxxi, 
fig. 8. 
Spirifera undifera Davidson, 1865. Mon. Brit. Devon. Brach., p. 36, pl. vii, figs. 1-10; 
also, var. undulata, ibid., figs. 11-14. 
compactus Meek, 1868. Trans. Chicago Acad. Sci., vol. i, p. 102, pl. xiv, figs. 
lla-d. 
undiferus, var. Takwanensis, Kayser, 1882. China, Richthofen, vol. iv, p. 86, 
tab. xi, figs. 1, 1 a-e. 
Compare Spirifera jimbriata (Conrad, 1842) Hall, 1867, Pal. N. Y., vol. iv, p. 214, pl. 
33; also, S. subundiferus M. & W., 1868. Geol. Surv. Dlinois, vol. iii, p. 
434, pl. x, figs. 5 a-e, and 8. (I.) Richardsoni Meek, 1868. Trans. Chicago 
Acad. Sci., vol. i, p. 104. 
But one specimen of this species was found among the Devonian 
Brachiopods brought from the Eureka District in 1880. That differed so 
much from a typical specimen of Spirifera (M.) undifera, kindly sent to me by 
Mr. Davidson, who received it from Dr. Roemer, that I gave it a specific 
ame in manuscript, comparing it to S. (M.) fimbriata Conrad. During the 
field season of 1882 a large number of specimens were collected from the 
Lower Devonian of the same district that afford the means for a more 
extended comparison with S. (M.) undifera and S.(M.) fimbriata. 
The variety shown by figs. 11, 114-2, of plate xiv (the original speci- 
men found in 1880), has the beak of the ventral valve so closely incurved 
that the narrow area and the foramen are almost entirely concealed; the 
few broad, rounded plications are crossed by concentric striz, with inter- 
spaces between of a little over one millimeter in width; on these, between 
the striz, radiating interrupted strize occur that are precisely similar to those 
on specimens of S. (JZ.) fimbriata Conrad, now before me, from the Upper Hel- 
derberg Group of New York, except that they are somewhat finer. On the 
shells of this species from the shales of the Hamilton Group these radiating 
strie reach their maximum development, appearing as elongate, radiating 
tubercles on the interspaces between the imbricating striz. Among the 
Eureka specimens individuals occur that show the concentric striz about 
