386 



BRACHIOPODA. 



[TRI. 



and truncated by a small, round per- 

 foration, separated from the hinge-line 

 by a deltidium; deep, triangular pit 

 beneath the beak of the ventral valve, 

 which is filled by the closely incurved 

 beak of the dorsal valve ; structure 

 punctate. Type T. costata and T. mul- 

 tistrlata. 



acadia?, Hall, 1860, Can. 

 Nat. and Geo.,vol. 5, p. 

 144, Up. Sil. 



camura, Hall, 1852, 

 FIG. 630. Trema- (Atrypa camura,) Pal. 

 tospira acadise. N. Y., vol. 2, p. 273. 



Low. Held. Gr. 

 costata, Hall, 1859, Pal. N. Y., vol. 3, p. 



210, Low. Held. Gr. 



deweyi, see Rhynchospira deweyi. 

 formosa, see Rhynchospira formosa. 

 gibbosa, Hall, 1860, 13th Rep. N. Y. Mus. 



Nat. Hist., p. 82, and Pal. N. Y., vol. 4, 



p. 272, Ham. Gr. 

 globosa, Hall, 1857, 10th Rep. N. Y. Mus. 



Nat. Hist., p. 87, and Pal. N. Y., vol. 3, p. 



215,(Waldheimiaglobosa,)Low.Held.Gr. 

 granulifera. Meek, 1872, Proc. Acad. Nat. 



Sci. Phil., p. 318, and Ohio Pal., vol. 1, 



p. 128, Hud. Riv. Gr. 

 hirsuta, Hall, 1857, (Atrypa hirsuta,) 10th 



Rep. N. Y. Mus. Nat, Hist., p. 168, and 



Pal. N. Y., vol. 4, p. 274, Up. Held, and 



Ham. Gr. 

 imbricata, Hall, 1857, (Leptocoalia imbri- 



cata,) 10th Rep. N. Y. Mus. Nat. Hist., 



p. 108, and Pal. N. Y., vol. 3, p. 246, 



Low. Held. Gr. 

 infrequens, Walcott, 1885, Mongr. U. S. 



Geo. Sur., vol. 8, p. 151, Lower Devonian, 

 mathewsoni, McChesney, 1861, New Pal. 



Foss., p. 71, Niagara Gr. 

 multistriata, Hall, 1857, (Spirifer multi- 



striatus,) 10th Rep. N. Y. Mus. Nat. 



Hist., p. 59, Low. Held. Gr. 

 liniuscula, Winchell, 1866, Rep. Low. 



Peninsula Mich., p. 94, Ham. Gr. 

 (?) uobilis, Hall, 1860, (Rhynchospira 



nobilis,) 13th Rep. N. Y. Mus. Nat. 



Hist., p. 83, Ham. Gr. 

 perforata, Hall, 1857, (Spirifera perforata,) 



10th Rep. N. Y. Mus. Nat. Hist., p. 60, 



Low. Held. Gr. 

 (f) quadriplicata, see Rhynchotreta quad- 



riplicata. 

 rectirostris, Hall, 1856, (Waldheimia rec- 



tirostra,) 10th Rep. N. Y. Mus. Nat. 



Hist., p. 49, and Pal. N. Y., vol. 3, p. 



217, Low. Held. Gr. 

 simplex, Hall, 1856, Pal. N. Y., vol. 3, p. 



211, Low. Held. Gr. 



Trigonotreta, Konig, 1825, Icon. Foss. Sect., 

 p. 3. [Ety. trigorws, a triangle; tretos, 

 perforated.] Syn. for Spirifera. Meek, 

 concluding that S. cuspidatus men- 

 tioned by Sowerby in Minn. Conch., 

 vol. 2, p. 42, should be considered as 

 the type of Spirifera, proposed to retain 

 Trigonotreta for shells of the type of S. 

 striata, contrary to the views of most 

 authors. See Pal. Up. Mo., p. 18. 



TRIMERELLA, Billings, 1862, Pal. Foss., vol. 

 1, p. 166. [Ety. treis, three; meros, 

 part; ella, diminutive.] Large subo- 

 vate or subcircular ; valves convex; 

 beaks solid and transversely striated ; 



FIG. 631. Trimerella grandis. Cast of dorsal 

 valve. 



shell thick, and surface concentrically 

 striated ; area of pedicle valve longer 

 than wide ; deltidium large ; hinge 

 thick, elevated, rudely or slightly den- 

 tary ; cardinal facet large ; crescent 

 well defined ; platforms elevated and 

 doubly vaulted, occasionally solid and 

 slightly raised ; median plate in both 

 valves, longest in the brachial one. 

 Type T. grnndis. 



FIG. 632. Trimerella grandis. Cast of ventral 

 valve. 



acuminata, Billings, 1862, Pal. FOBS., vol. 



1, p. 167, Guelph Gr. 

 billingsi, Dall, 1871, Am. Jour. Conch., 



vol. 7, p. 82, Guelph Gr. 



