LAMELLIBRANCHIATA. 547 
Cyrtodonta grandis.] 
Casts of what may be a small variety of C. tenella occur in the Trenton limestone 
at Minneapolis. The largest seen (Mus. Reg. No. 700), is only 12 mm. long. Aside 
from the matter of size, they agree very well indeed with the types of the species. 
Formation and locality.—Upper part of middle third of the Trenton shales, about six miles south of 
Cannon Falls, Minnesota. 
Mus. Reg. No. 8336. 
Cyrtoponta GRanpis Ulrich; and varieties. 
PLATE XL, FIGS. 9-14. 
Cypricardites grandis ULRICH, 1890. Amer. Geol., vol. vi, p. 387. 
Cypricardites germanus ULRICH, 1892. Nineteenth Ann. Rep. Geol. and Nat. Hist. Sur. Minn., p. 236. 
Cypricardites luculentus SARDESON, 1892. Bull. Minn. Acad. Nat. Sci., vol. iii, p. 338. 
Fig. 43. Cyrtodonta grandis, and varieties. a and b, anterior and lateral views of a perfect speci- 
men, upper Trenton, two miles south of Burgin, Kentucky. c¢ and d, lateral and antero-cardinal views 
of a small left valve of same, with stronger surface markings than usual; from same formation and 
locality. e, nearly entire cast of the interior of a left valve, from same locality. jf, small fragment of 
a cast of the interior of a left valve, preserving sharp impressions of the anterior adductor scar and 
cardinal teeth. g, the cardinal part of a cast of the interior of a right valve, drawn without the beak 
so as to show the entire hinge. i, hinge of specimen shown in figure ec and d@. j, original type of C. 
germana, restored; hinge of same figured on plate xu. k, interior of two left valves of C. grandis var , 
intermedia, n. var.; Trenton, Haynie’s Mill, Tennessee. 
