PLATE IXa—C ontinued. 
Fig’. 14. A cardinal view of the specimen illustrated on plate ix, tig. 1. 
Trenton limestone. New York. 
Fig. 15. An enlarged view of the interior of a pedicle-valve; showing the vascular markings, which are 
rarely seen in this species. 
Hudson River group. Waynesville, Ohio. 
Strophomena ? (Strophonella ?) patenta, Hall. 
(The actual relations of this species to Strophomena and Strophonella are not yet fully determined.) 
Fig. 16. The interior of a large pedicle-valve ; showing the muscular area. 
Fig. 17. The exterior of the pedicle-valve. 
Fig. 18. The interior of a smaller pedicle-valve. 
Clinton group. Reynale's Basin, N. Y. 
Genus ORTHOTHETES, Pander. 
Page 253. 
Orthothetes subplana, Conrad. 
(See Plate IX, figs. 21-29.) 
Fig. 19. An enlargement of the central cardinal portion of the brachial valve ; showing the great develop¬ 
ment of the deltidial callosity, the rounded, somewhat unequal lobes of the cardinal process, 
and the thin, abrupt, nearly vertical crural plates. X 3. 
Niagara group. Waldron, Indiana. 
Orthothetes injequalis,* Hall. 
Fig. 20. The interior of a pedicle-valve. 
Fig. 21. A small brachial valve ; showing a tendency to a fasciculation of the strise. 
Fig. 22. A cardinal view of an infernal cast of the brachial valve. 
Fig. 23. The interior of a brachial valve. In this figure the lobes of the cardinal process are not suffici¬ 
ently distinguished from the crural plates. 
Waverly group (Kinderhook). Burlington, Iowa. 
Orthothetes inflatus, White and Whitfield. 
Fig. 24. A cardinal view of one of the original specimens, which is an internal cast of the brachial valve ; 
showing the impression of the cardinal process and adductor muscles. 
Fig. 25. The cardinal process, enlarged from a gutta-percha impression ; showing its appearance on the 
anterior face. The crural bases (x) appear very abrupt at the termination on account of the 
impression having been taken without the shell being first entirely removed from the matrix. 
Waverly group (Kinderhook). Burlington, Iowa. 
Orthothetes desideratus, n. sp. 
Fig. 26. A view of the brachial valve of an internal cast; showing the muscular impressions. 
Fig. 27. A cardinal view of the same specimen. 
Waverly group. Ohio. 
* The reference to this species in the Report of the New York State Geologist for 1882, explanation of plate xi a (= ix a) 
as Streptorhynchus cequivalvis, is erroneous. The shell is the Orthis inequalis, Hall, Geol. Rep. of Iowa, p. 490, plate ii, figs. 
