BRACHIOPODA. 193 



crossed by much finer concentric striae; a single central one, and sometimes two or three 

 of the striae upon the mesial sinus, are much stronger than the otheis; and there is some- 

 times an impressed line down the centre of the dorsal valve. 



"[Remarks] — The inner margins of the shell are denticulate, but this character is 

 not shown in well-preserved specimens; it is seen in the casts, and upon the edges of 

 the shell when worn from the exterior." — Hall, 1859. 



Remarks — Only one specimen has been observed. 



Genus Uncinulus Bayle 



Uncinulus nudeolatus (Hall) 

 Plate 49, figures 3-16 



Rhynchonella nucleolata Hall, 1857 (in part), 10th Ann. Rept. N. Y. State Cab. Nat. 



Hist., p. 68. 

 Rhynchonella nucleolata Hall, 1859 (in part), Pal. N. Y., vol. Ill, p. 227, pi. XXXI, 



figs. 2 f-i, k-p, r-u, x, y, (not figs. 1 a-c= U. globulus, 1 d-f and 2 a-e= U. globulus), 



1861. 

 Rhynchonella nucleolata Billings, 1863, Proc. Portland Soc. Nat. Hist., p. 110, pi. 3, 



fig. 5. 

 Uncinulus nucleolata Hall and Clarke, 1893, Pal. N. Y., vol. VIII, pt. II, p. 199. 

 Uncinulus nudeolatus Girty, 1899, U. S. Geol. Surv., 19th Ann. Rept., pt. Ill, p. 564. 

 Uncinulus nudeolatus Weller, 1903, Pal. N. J., vol. Ill, p. 284, pi. XXIX, figs. 6-9. 

 Uncinulus nudeolatus Shimer, 1905, N. Y. State Mus., Bull. 80, p. 245. 

 Uncinulus nudeolatus Schuchert, 1913, Md. Geol. Surv., L. Dev., p. 365, pi. LXIV, 



figs. 16, 17. 



Description — "Shell varying from spherical to spheroid-pentagonal ['this refers to 

 the forms * * * * taken out and named U. globulus' 1 ] or subpentagonal. Ven- 

 tral valve convex or depressed convex, abruptly deflected towards the margins; beak 

 small, depressed, closely incurved over that of the opposite valve, often subangular on 

 its lateral margins. Dorsal valve larger, sometimes very gibbous, often a little de- 

 pressed towards the beak; beak never prominent. Surface marked by fifteen to twenty- 

 three simple rounded plications, about four or five of which are slightly elevated to- 

 wards the front of the dorsal valve into a mesial prominence, and three to five depressed 

 on the ventral valve, so as to form a more or less distinct sinus, which never extends 

 beyond the middle of the shell. These depressions are prolonged in front into a more 

 distinct linguiform extension fitting into a corresponding sinus in the front of the oppo- 

 site valve, and sometimes curved inwards beyond the plane of a right angle with the 

 back of the valve,"— Hall, 1859. 



Remarks — The specimens at hand have from about 20 to about 34 plications on 

 each valve, from 4 to 6 plications on the fold, and from 3 to 5 plications in the sinus, 



Uncinulus mutabilis (Hall) 



Plate 49, figures 17-22 



Rhynchonella mutabilis Hall, 1857, 10th Ann. Rept. N. Y. State Cab. Nat. Hist., p. 66, 



figs. 1-7. 

 Rhynchonella mutabilis Hall, 1859, Pal. N. Y., vol. Ill, p. 225, pi. XXIX, figs. 4 a-p; 



pi. XXX, figs. 1 a-e, 2 a-i, k-p, r, s, 1861. 

 Uncinulus mutabilis Hall and Clarke, 1893, Pal. N. Y., vol. VIII, pt. II, p. 199, pi. 



' LVIII, figs. 22-25, 1894. 

 Uncinulus mutabilis Weller, 1903, Pal. N. J., vol. Ill, p. 283, pi. XXIX, figs. 1-5. 



•Schuchert, C, Md. Geol. Surv., L. Dev., p. 365, 1913. 

 7 



