The Fauna of the, Magnesian Series. 103 



from side to side, and the sutures curve forward above and below and back- 

 w^ard across the sides. The depth of the chamber of habitation is not 

 known. The septa are very close together, eight or ten falling in a length 

 equal to the transverse diameter. The siphuncle is small, marginal and 

 flattened next the outer wall. Transver section of the shell oval. The 

 surface of the shell is not preserved on any of the specimens, but the casts 

 are smooth. 



Found near Dresbach, Winona county, Minnesota, among other fossils 

 from the Oneota dolomite. 



Endoceras consuetum n. sp. 

 Plate VI, figure 11. 



The shell long, straight, slowly expanding. The chamber of habitation 

 is deep, about two and one-half to three times as deep as high. Transverse 

 section vertically suboval, with the outline of the siphuncle circular and 

 about one half as great in diameter as the shell. Siphuncle close to the ven 

 tral side. The septa are close together and concave. The sutures arch 

 forward slightly near the dorsum and apparently backward on the ventral 

 side, and in general they are oblique to the longitudinal axis. The shell 

 was very thin, and on the cast leaves indistinct undulating growth lines 

 along the body portion, parallel to the sutures of the septate portion. 

 There is a concave band on the surface ot the first septum on the specimAi, 

 near the siphuncle, but which may be due partly to distortion. 



From near the top of the Shakopee at the crossing of the Chicago, 

 Milwaukee and Saint Paul and the Illinois Central railways, ten miles west 

 of Monroe, Wisconsin, and one-halt mile below Pickett station. 



Piloceras corniculum n. sp. 

 Plate VI, figures 5, 6 and 7. 



The siphuncles of four shells have been found as quartz casts. These 

 show a rapidW, uniforml3' expanding shell of small size. The sutures on 

 the siphuncle are distant about one-fourth the vertical diameter of the 

 same, but on different specimens have a varying direction. The concavity 

 of the septa appears to decrease as the shell increases and their apices are 

 not uniformly directed on different specimens, and in one case the apex is 

 toward one side, A transverse section of the siphuncle is vertically oval, 

 on all alike. A third specimen, not figured, retains a portion of the outer 

 surface and septa, and indicates the position of the siphuncle asclose to the 

 dorsal (concave) side and its diameter aboutone-half thatof the shell. Sur- 

 face of the shell probably smooth. 



Without an extensive series of specimens it is quite impracticable to de- 

 termine whether one or two species are here described, but the great varia- 

 tion of some characters seen in the specimens at hand seems to indicate 

 strong variability rather than specific difference. 



From the Oneota dolomite, nearDresbach, Winona county, Minnesota, 



