LAMELLIBRANCHIATA. 549 
Vanuxemia.] 
-Fig. 9 of plate XL, represents what appears to be a large right valve of germana. 
The specimen is preserved as a partial mould of the exterior. Another specimen 
from the Galena near Wykoff may be said to be identical in its characters with the 
original types of germana. The specimen represented by fig. 10 is one of a number 
in which the balance of agreements is with the variety rather than with typical 
grandis, while the original of fig. 11 was made by a small right valve of which the 
opposite seems to be true. 
Another variety was found in the Trenton of Tennessee by Prof. Jas. M. Safford, 
and sent to me for examination. The illustrations show that in its outline and 
general appearance this new variety closely simulates variety germana and C. tenella. 
It differs, however, in the teeth which are stronger and more curved than in those 
forms, being on the whole more like those of C. grandis and C. saffordi. As it marks 
another stage in the development of this type of shells it should receive aname. I 
propose therefore that it be called Cyrtodonta grandis, var. intermedia. 
Mr. Sardeson has given the name luculenta (loc. cit.) to a Hudson River form of 
which the hinge and exterior of two fair examples are represented on Plate XL, by 
figs. 13 and 14. This form I cannot now regard as specifically distinct from C. grandis, 
since it is almost identical with var. germana, the only difference being small ones 
in the hinge and that the umbones are somewhat larger in the Juculenta. 
Two other stages in the development of this series of shells, in these cases per- 
haps of specific importance, occur in the upper beds of the Cincinnati group at Rich- 
mond, Indiana. These I hope to describe in another publication. 
Formation and locality.—The types of C. grandis and the var. germana, are from the upper Trenton 
between Burgin and Danville, Kentucky. Casts of the species and variety have been found in the middle 
and lower Galena near Cannon Falls, Kenyon, Pleasant Grove, Wykoff, Lime City, and other localities in 
Minnesota; at Decorah, Iowa, and Oshkosh, Wisconsin. The variety intermedia is so far known only 
from the Trenton at Haynie’s mill, in Tennessee, where it occurs in association with Vanuxemia hayniana 
Safford, sp. The var. lwculenta occurs in the shaly limestones of tae Hudson River group at Granger and 
other localities in Fillmore county, Minnesota. 
Mus. Reg. Nos. 8337, 8347, 4102, 8360, 8333. Var. luculenta 8332. 
Genus VANUXEMIA, Billings. 
Vanuxemia, BILLINGS, 1858. Rep. of Progr. Geol. Sur. Can., p. 186. 
Shells ventricose, oblique, acuminate ovate to subcircular; anterior end very short 
_ and small, the posterior broadly rounded. Umbones full, prominent, beaks strongly 
incurved. Surface with concentric growth lines only. Hinge strong, with teeth 
as in Cyrtodonta, two to four, rarely more, cardinal, and two to four posterior lateral 
teeth in each valve. Teeth frequently striated transversely, an elongated ligamental 
area generally present. Two adductors, the anterior depression very sharply defined 
and deep, and situated in a prolongation from the anterior end of the hinge plate; 
