1044 THE PALEONTOLOGY OF MINNESOTA. 



LTroehonematldtc. 



these Mr. Ulrich proposes to establish and add two new genera which he regards as 

 related to Cyclonema. The first of these he names DYERIA, in memory of the late 

 C. B. Dyer, a former well-known collector at Cincinnati; the other BUCANOSPIRA, in 

 allusion to the trumpet-like expansion of the aperture. Both of these genera may 

 prove to have closer relations to Platyceras than we now believe.* 



FIG. 8. Two views of a large specimen of Dyeria costata James sp. from the upper half of the Lor- 

 raine group at Cincinnati, Ohio. Collection of E. O. Ulrich. 



Dyeria is founded on a Cincinnati fossil originally described by Mr. U. P. James, as Cyrtolites costatusj 

 but since 1875 known to collectors as Bucania costata. Heretofore it was supposed that its whorls were 

 co led in the same plane, but, as may be seen from the accompanying illustrations of a full-grown speci- 

 men, this is not the case. Still, the coiling of the whorls may be more nearly in one plane than in the 

 figured specimen indeed, in one case before us the last whorl turns upward instead of downward 

 According to our opinion Dyeria costata, as it should now be called, is in no wise related to any member of 

 the Belkrophontacea, but on the contrary is not far removed from Cyclonema. The surface sculpture is of 

 a type pertaining quite generally to that genus, even to the matter of the transverse wrinkles or undula- 

 tions on the last whorl of old examples. It is true the margin of thulipand, therefore, the lines of 

 growth, take a more undulating course in circling the whorls than in any Cyclonema known to us, but 

 when a sinus does occur in the lip of a Cyclonema it is in a corresponding region or regions. However, 

 Dyeria differs widely from that genus in the depres-ed almost involute form of its shell, in having a 

 considerable part of the last whorl vagrant and nearly straight, and in the simple untfiickened character 

 of the inner lip. It remains to be seen whether the vagrant character of the last whorl is essential or 

 not. If it is not then the genus may justly include forms like Lindstrotn's Euomphalus tuba. 



Fio. 9. liucanospira expansa, a. gen. et sp. (Ulrich), Niagara group, Wayne county, Tennessee, a 

 and 6, slightly restored views, X2, of a siliclfled shell, showing the expanded aperture, remains of preced- 

 ing expansions (at a and b on fig. a), and surface markings; c, under side of the interior cast of a larger 

 specimen with indications of numerous successive apertural expansions. The umbilicus is relatively 

 larger and the spire lower in this specimen than in the first. Collection of E. O. Ulrich. 



Bucanospira is based on an undescribed Upper Silurian shell from western Tennessee, for which we 



The Pla/i/cerhJ'E arc greatly In need of revision. While the majority are doubtless referable to the capulids. many 

 others belong near Cycloncma and Dyerla among the Trochonem'iliilir. Or. If that arrangement Is not acceptable, then the latter 

 family will have to be restricted to Troch >nemi and Cyclonema, and Slri>iilni*tiilui (which we extend so that it Includes shells 

 MII n >nly arraiiecl under d/cloiwmi), together with Hulupea, Dyeria and /! nius/.ir removed to the L'alyptrtvidrc; or a new 

 Intermediate family must be Instituted for their reception. 



+ A Tier. Jour. Sol. and Art*, 3d ser., vol. Ill, p. 26, 1872; see also Meek, 1871), Pal. Ohio, vul. I. p. lf>0, pi. XIII, figs, la.le. 



