INVERTEBRATES. 381 



stages of growth, while its inner lip is less developed, and its columella is not 

 provided with a ridge or angle, as in the typical species of Eunema. 



From the genus Turritella, some species of which our shell resembles in form 

 and general appearance, it differs in its slightly effuse and less rounded aperture, 

 disconnected peristome and straight outer lip. It is probably more nearly allied 

 to Loxonema than to any of the groups we have mentioned, but presents the 

 well marked differences of being provided with distinct revolving carinse and a 

 straight instead of a sigmoid outer lip and lines of growth. It will probably 

 include several species of Turritella-like shells from the Coal Measures. 



Orthonema Salteri, M. and W. 



PI. 31, fig. 14a, 146, 14c. 



Eunema? Salteri, Meek and Worthen, October, 1860. Proceedings Acad. Nat. Sci , 

 Philad., p. 464. 



Shell small, elongate-conical, acutely pointed at the apex. 

 Volutions about thirteen, vertically flattened around the middle 

 and sloping obliquely to the suture above, increasing gradually 

 in size ; last one angular around middle, and a little convex, but 

 not much extended below ; suture linear, rather well defined. 

 Aperture ovate, angular above, and rounded or slightly effuse on 

 the inner side below; outer lip thin, and nearly straight; inner 

 lip but slightly developed; columella arcuate. Surface orna- 

 mented by three rather distinct revolving lines or carinas, two of 

 which occupy the upper margin of the whorls, while the third 

 is placed just above the suture, on the spire, but passes around 

 the middle of the last turn. Lines of growth small, rather 

 obscure, and nearly straight from the suture until they reach 

 the under side of the body whorl, where they arch a little for- 

 ward, and then curve backwards to the base of the columella. 

 A single revolving, impressed line is sometimes seen below the 

 angle, on the under side of the last turn. Length, 0.50 inch; 

 breadth, 0.17 inch. Length of aperture, 0.17 inch ; breadth, 

 0-.10 inch. Apical angle convex, divergence 23°. 



Locality and "position: Hodge's creek, Macoupin county, Illinois; Lower 

 Coal"Measures. 



