PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 187 
EXPLANATION OF PLATE VIII.* 
SOLENISCUS? (MACROCHEILUS) PONDEROSUS Swallow? 
Figs. 1,2.—Opposite views of a large example from Southern Iowa. The outer lip 
and a portion of the columella have been broken away so that the obtuse 
fold is not clearly shown. Professor Swallow’s species was never figured ; 
and this form is doubtfully identified by means of his description. (Museum 
No. 9142.) 
SoOLENISCUS? (MACROCHEILUS) PRIMIGENIUS Conrad. 
Fig. 3.—Lateral view of a damaged example from Illinois, showing the thickened 
columella, but only a slight trace of a fold. (Museum No. 747.) 
SOLENISCUS (MACROCHEILUS) FUSIFORMIS Hall.t 
Fies. 4,5, 6.—Different views of two examples from Illinois, showing some variation 
in the outward form of the shell, and also the character of the columella. 
Fig. 5 shows the character of the inner lip at mature growth; and Fig. 6 
shows the columella with its fold and broad groove after a portion of the 
last volution has been removed. 
SOLENISCUS (MACROCHEILUS) NEWBERRY! Hall. 
Figs. 7,8.—Opposite views of an example from Illinois, showing the outward form, 
the accumulation of callus upon the inner lip, and the columellar fold and 
broad groove. 
SOLENISCUS PLANUS White. 
Fias. 9, 10.—Opposite views of an example from Illinois, showing the outward form, 
and the columella with its fold and groove. Thisform is possibly identical 
with the Macrocheilus newherryi of Hall; but it seems to be different. 
SOLENISCUS (MACROCHEILUS) VENTRICOSUS Hall. 
Fis. 11, 12.—Lateral views of two Illinois examples. Fig. 11 represents an apertural 
view of a nearly perfect shell; and Fig. 12, another shell from which a large 
part of the last volution has been removed, to show the columella with fold 
and groove. (Museum Nos. 9372 and 12210.) 
SOLENISCUS (MACROCHEILUS) TEXANUS Shumard. 
Figs. 13, 14.—Opposite views, showing the outward form of the shell, and the char- 
acter of the calumella with its fold and groove. Dr. Shumard’s species was 
never figured, and this form from the Coal Measures of Illinois has been 
doubtfully identified by means of his description. 
SOLENISCUS? (MACROCHEILUS) MEDIALIS Meek & Worthen. 
Figs. 15, 16.—Opposite views of an example from Indiana, showing the outward form 
and the columella, which bears only a slight trace of a fold. 
SoLENISCUS (MACROCHEILUS) PALUDINZFORMIS Hall. 
Fic. 17.—Lateral view of an example from Indiana, with a part of the last volution 
removed, showing the columellar fold and broad groove. 
SOLENISCUS TyPICUS Meek & Worthen. 
Fies. 18, 19.—Copies of Meek & Worthen’s figures of their type-specimen. 
All figures on this plate are natural size. 
* This plate is also to appear in the annual report of the Indiana State Geological Survey; and the 
use of a part of the examples here figured have been courteously loaned for the purpose by Prof. John 
Collett, State Geologist. 
+The name Macrocheilus fusiformis was preoccupied by Sowerby. Professor Hall's species belongs 
to the group which I refer to Soleniscus. If this view is accepted, and Sowerby’s species also belongs 
to that group, the name of the American species must be changed. 
