Bracliiopoda from the Bokkeveld Beds. 171 



of ribs varies from 110 to 130 on the margin, and though they 

 appear a httle coarser in Ortli. sulivani, this is apparently only 

 due to the state of preservation. The mode of increase is precisely 

 similar, and the faint sinus noticed by Sharpe in Str. bainii is also 

 clearly developed in his figured specimens of Orth. sulivani. 



Affinities. — This species is closely allied or perhaps identical with 

 Orth. agassizi Hartt," from the Devonian of Brazil, and may not be 

 specifically distinct from Ulrich's Orthothetes sp. « t from the 

 Huamampampa Sandstone (Devonian) of Bolivia. It is also a near 

 relative of Orth. chemungensis Conrad, | from the Chemung Group 

 of North America. The widespread Orth. umhraculum Von Buch, 

 also shows considerable affinity. 



Localities. — (No. 157) Uitkomst, Ceres (slab crowded with 

 examples of this species). (No. 113) ditto. (No. 210) Gydo Pass, 

 €eres. (No. 212) Wolvaart's Farm, near Ceres Village. 



Family PEODUCTID^. 



CHONETES FALKLANDICUS Morris and Sharpe. 

 (Plate XX., figs. 9, 10.) 



1846. Chonetes falklandica, Morris and Sharpe, Quart. Journ. 



Geol. Soc, ii., p. 274, pi. x., fig. 4. 

 1893. Chonetes falklandica, Von Ammon, Zeitschr. Gesell. f. 



Erdkiinde, Berlin, Bd. xxviii., p. 360, fig, 5, a, b. 

 1897. Chonetes falklandicus, Schuchert, Syn. Amer. Foss. Brach. 



(Bull. U.S. Geol. Surv., No. 87), p. 173. 



The description given by Morris and Sharpe of this species is as 

 follows: "Transversely semi-oval; upper valve convex, with a 

 slight mesial depression ; lower valve rather concave ; surface 

 covered with fine bifurcating rays, crossed by a few concentric lines 

 of growth. Hinge-area linear, of the breadth of the shell ; hinge- 

 line furnished with fine spines. Width ^ inch ; length ^ inch." 



There is one shghtly distorted and imperfect impression of a 

 pedicle valve and the internal cast of another on the same rock- 



* Kathbun, Bull. Buffalo Soc. Nat. Hist., i., 1874, p. 248, pi. ix., figs. 3, 4, 10, 

 16, 17, 23, 2.5, 26, 28-30. 



t Ulrich, Neues Jahrb. f. Min., Beil. Bd. viii., 1893, p. 76, t. iv., fig. 30. 



+ Hall and Clarke, Palffiont. N.Y., vol. viii., pt. 1, 1892, p. 255, pi. x., fig. 9, 

 pi. xi.a, fig. 14. 



