Preliminary Notes on Cincinnatian Fossils 22/ 
pears to have been lost, and no figuie was published of this type 
specimen. 
Cyclocoelia sordida, Hall. 
Paleontology of New York, vol. i, p. 148, 1847. 
The type of Orthis sordida, preserved in the American Museum 
of Natural History, in New York City, is evidently a Cincinnatian 
species belonging to the group of Orthis ella. It has 21 primary 
plications, and one intercalated plication. In the description of 
Orthis ella, 15 to 20 simple plications are mentioned. The types 
of Orthis elia preserved in the American Museum of Natural 
History include 5 entire specimens. Of these three have 18 or 
19 plications, a fourth specimen has 21 plications, and the fifth 
specimen, not typical according to the description, has 27 plica- 
tions of which between 5 and 7 plications evidently are intercalated 
within I millimeter from the beak. Orthis ella does not form even 
a variety of Orthis sordida, but should be regarded as an exact 
synonym. 
The pedicel valve has an open triangular delthyrium; the hinge 
teeth are supported by diverging vertical plates which extend only 
about two millimeters from the beak in case of shells having a 
length of 7 millimeters. Cross sections do not indicate the pres- 
ence of any muscular area. No distinct hinge area is present. 
The brachial valve possesses two crural plates which appear to be 
rather broad and to terminate anteriorly in a point. A sharp me- 
dian striation extends forward to almost 3 millimeters from the 
beak. No loops or spiralia were detected. One specimen ap- 
peared to show a short narrow cardinal process. All other speci- 
mens failed to give any definite information. The exact definition 
of this genus awaits further study. The term Cycloccelia therefore 
can not he said to have established value, but it will serve at least 
to remove to a separate group a number of species, including Orthis 
sectostriata, Ulrich, which at present have no distinctive desig- 
nation. 
Rhynchotrema dentata — arnheimensis, var. nov. 
{Plate IV, Fig. 12.) 
The type of Rhynchotrema dentata was obtained from the Rich- 
mond group in some part of Ohio or Indiana. It appears to be 
an immature specimen of the Whitewater form, as found at Rich- 
