230 Twenty-fourth Report on the State Museum. 



one forms fully one-half of the length of the shell ; aperture very 

 long and narrow ; columella very much produced ; canal broad and 

 shallow; outer lip directed forward in the middle. 



This species resembles the F. vittctta {Murchisonia vittata of 

 Pal. N. Y., Yol. I, p. 181, pi. 39), but differs in the form of the volu- 

 tions and in being more produced below than any of the specimens 

 of that species. 



Length of the four last volutions three and three-fourth inches, 

 diameter of body whorl one incli and one-fourth. 



Forination and locality. In the Trenton limestone, half a mile 

 west of Elkader, Iowa. 



FUSISPIRA TEREBKIFOEMIS U. 8]). 



Plate 8, fig. 4. 



Shell terete, acnte (subfusiform), consisting of about six, gradually 

 increasing, depressed-convex volutions, the last one of which forms 

 about two-fifths of the entire length of the shell, exclusive of the 

 anterior prolongation ; aperture narrow, obliquely elliptical, strongly 

 modified above by the preceding volution, and prolonged below, 

 forming an extended canal. 



Surface apparently smooth. Apicial angle about thirty degrees. 



Formation and locality. In the Hudson-river group, at Cincin- 

 nati, Ohio. 



Ctetolites Dyeei n. sp. 

 Plate 8, figs. 7, 8. 



Shell small, laterally compressed, consisting of two or more volu- 

 tions, the outer one embracing the inner for about half its breadth, 

 bearing a moderately wide umbilicus, in which may be seen a portion 

 of the preceding volution ; sides of the volution convex, obtusely 

 subangular near the margin of the umbilicus into which it curves 

 abruptly and more gradually declines with a slight convexity, toward 

 the salient subcarinate dorsum. Transverse section cordiform, broad- 

 est near the umbilical margin. 



Surface of shell marked by from eight to twelve nearly equidistant 

 revolving ridges, with sometimes smaller intermediate ones, and also 

 crossed by numerous closely arranged transverse lamellose ridges 

 having a double backward flexure between the revolving lines, and a 

 general retral direction towards the keel of the shell. 



This species differs in the character of its surface markings from 

 any of the forms lieretofore described. 



Formation and locality. In the shales of the Hudson-river group 

 at Cincinnati, Ohio. From the collection of Mr. C. B. Dyer. 



