512 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Subfamily TriroecH1InaAE Ulrich and Cooper, 1936 
Tritoechiidae without a spondylium, the dental plates extending directly to 
the floor of the valve. 
Genus TRITOECHIA Ulrich and Cooper, 1936 
Tritoechia Utricu and Cooper, Journ. Paleont., vol. 10, No. 7, p. 624, 1936; Geol. Soc. Amer. 
Special Pap. 13, p. 160, 1938. 
TRITOECHIA TYPICA (Ulrich) 
Plate 77, A, figures 1-9 
Deltatreta typica Ulrich in ScHUCHERT and Cooper, Mem. Peabody Mus. Nat. Hist., vol. 4, 
pt. I, p. 206, pl. 6, figs. 10, 14, 19 (lectotype), 30, 1932. 
Tritoechia typica (Ulrich) UtricnH and Cooper, Geol. Soc. Amer. Special Pap. 13, p. 1609, 
pl. 33B, figs. 7-28, 1938. 
Interior and exterior views of this genus and species are introduced for com- 
parison with the rare genus Eremotoechia. From present knowledge the latter 
appears to be related to the common Lower Ordovician (Canadian) genus. 
Types.—Lectotype: 91749c; paratypes: 91749a,b,d; hypotypes: 91750a-m ; 
92985a-l. 
Horizon and locality —Kindblade formation, Arbuckle Mountains, Okla. 
Subfamily PoLtyToEcHINAE Opik, 1934 
Genus POLYTOECHIA Hall and Clarke, 1892 
Polytoechia HAtt and CLarKE, Pal. New York, vol. 8, pt. 1, p. 239, 1892.—ULRIcH and 
Cooper, Geol. Soc. Amer. Special Pap. 13, p. 175, 1938. 
POLYTOECHIA ? OAKENSIS Butts 
Polytoechia ? oakensis Burrs, Alabama Geol. Surv., Special Rep. 14, p. 116, pl. 26, figs. 25, 26, 
1926. 
This is a shell of uncertain generic affinities, which has never been described. 
It is known only from two pictures in Butts’ report on Alabama geology. The 
specimen is small, measuring 8.7 mm. long, 9.4 mm. at the middle, which is the 
widest part, 7.2 mm. along the hinge, 5.7 mm. thick, and the brachial valve is 
7.7 mm. long. The pedicle valve has a broad interarea which is steeply apsacline. 
The beak is slightly incurved. The delthyrium is open. The brachial valve is 
moderately convex in both profiles, and both valves show traces of fine radial 
ornament. 
The valves are so heavily silicified that few pertinent details can be seen 
through the delthyrium. A thickening at the beak which forms a moderately 
deep V suggests the presence of a spondylium. No details of the brachial valve 
interior can be determined. 
The general aspect of this shell suggests the genus Polytoechia, but no trace 
of a pseudodeltidium can be detected. The specimen also suggests Butts’ Poly- 
toechia symmetrica which Ulrich and Cooper (1938, p. 144) assigned to the genus 
