The Fauna of the Magneslan Series. 101 



The first specimens seen of this species were collected by Mr. A. D. 

 Meeds, of the University of Minnesota. The name is given in honor of Dr. 

 David Dale Owen. 



Raphistoma ruidum n. sp. 



Plate V, figrures 13 and 14.. 



Shell of four or more volutions rising in a low spire. The volutions are 

 convex above with a narrow concave area along the periphery. Below, the 

 surface of each is moderately convex along the periphery and strongly con- 

 vex next the umbilicus, but gently concave for the greater distance bet ween 

 these two areas. The umbilical surface is flattened also and is the shortest 

 of the four sides of the subquadrate figure presented by across section. The 

 outer side next the umbilicus is the longest, and the sides are about in the 

 relation of 5, 6, 7 and 8. The umbilicus is wide and deep. 



A cast of the interior shows that the shell was ornamented by sharp 

 elevated striae of growth. These are evident also on casts of the interior, 

 and curve obliquely back for a distance greater than one-eighth of a volu- 

 tion and suddenly out in a reversed curve near the acute edge of the volution. 



Specimens of this species were found near Argyle, Wisconsin, in the 

 Shakopee formation, and at Shakopee, Minnesota, in the quarry at that 

 place. Also near Cannon Falls, in the Shakopee formation. 



Straparollus intralobatus n. sp. 

 Plate V, figure 20. 



Coil small, of three to four volutions, in the same plane, or nearly so, 

 and in close contact. The aperture is transversely oval except where in- 

 dented on the inner margin by the penultimate volution. The surface of 

 the cast is marked by growth lines that are rather variable and indefinite 

 and run a little backwards near the dorsal side. 



Found at Altura, Winona county, above the middle of the Oneota dol- 

 omite. ' 



Subulites exactus n. sp. 

 Plate VI. figure 14. 



Casts of the interior of shells of this species show a long, slender spiral 

 ^f twelve or more whorls in all. The accompanying figure shows a cast of 

 probably the fifth to eighth whorls. The whorls are gently convex on the 

 outer surface, but are more strongly rounded near the sutures, which are 

 wide and deep on the casts and appear to have been equally strong on the 

 exterior of the shell. Surface marks can not be detected and the form of the 

 aperture is not well shown but must have been elongate, rounded very nar- 

 rowly above and more broadly below, and with the centersof the inner and 

 outer lips somewhat increased in convexity. 



Found at Shakopee, Minnesota, in the Shakopee dolomite, and in the 

 same formation near Cannon Falls, Minnesota. ' 



