PuaTE VIII.* 
(For text see pages 184-187.) 
SOLENIsSCUS? (MACROCHEILUS) PONDEROSUS Swallow ? 
Fics. 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 isnot clearly shown. Professor 
Swallow’s species was never figured; and this form is doubtfully identified by means of 
his description. (Museum No. 9142.) 
SOLENIsCcUS? (MACROCHEILUS) PRIMIGENIUS Conrad. 
Fic. 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. ¢ 
Fias. 4,5, 6.—Different viewsof two examples from Ilinois, 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 portionof the last volution has been removed. 
SOLENISCUS (MACROCHEILUS) NEWBERRYI Hall. 
Fias. 7, 8.—Opposite views of an example from Illinois, showing the outward form, the accumulation 
of callus upon theinner lip, and the columellar fold and broad groove. 
SOLENISCUS PLANUS White. 
Fics. 9, 10.—Opposite views of an example from Illinois, showing the outward form, and the columella 
with its fold and groove. This form is possibly identical with the Macrocheilus Newberry of 
Hall; but it seems to be different. 
SOLENISCUS (MACROCHEILUS) VENTRICOSUS Hall. 
Fias. 11,12.—Lateral views of two Illinois examples. Fig. 11 represents an apertura] 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. 
Fics. 13, 14.—Opposite views, showing the outward form of theshell, and the character of the columella 
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 colu- 
mella, which bears only a slight trace of a fold. 
SOLENISCUS (MACROCHEILUS) PALUDINZFORMIS Hall. 
Fig. 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. 
Fics. 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 has 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. 
546 
