PLATE I. \\III. 



r\..i 



I to 6 RArmsToMA rKRACUTUM U. and 8 WO 



1 Outline rlew of the flat side of a specimen preserving the shell with some of t h>- 

 - ii r fact- marking*. Ctenodonta bed, Black Iiiv.-r group, near Cannon Falls, 

 Minnesota. 

 I Umbilical side of the same, xl 



3 AjH-rtural view of name. x2, showing extremely acute periphery and slightly 



sunken spire. 



4 Small portion of outer whorl of figure 1, x5, showing fine regular lines of growth 



<>f tin- delicate raised line Interrupting thflr continuity about a third of the 



width nf the whorl from the suture. 



6 Apical side of another example, from the same locality, 

 o Apertural view of same, x!. The spire Is not sunken In this specimen. 



Fig*. 7 to I:\I-III-IIIMA iiicimoNDENSE Ulrlch Ml 



7 and 8 Two views of a specimen retaining some of the shell. Richmond group, 



Richmond, Indiana. 



9 Small part of the upper side of the last whorl of same. x4, showing curvature 

 <>f the sub-equal striae and the wire-like peripheral edge. The latter forms 

 the lower boundary of the figure. 



Figs. 10 to 13 RAi'iusTOMiNA KUOATA U. and S 944 



Four views, the last of the natural size, the others *2, of an entire cast, 

 apparently of the exterior of the shell. The ununual strength of tin- 

 transverse striae Is the most striking of the specific peculiarities of this 

 species. Trenton group, Clllambonltes bed, Goodhue county, Minnesota. 



Fig*. 14 to IT R APiusTtixiNA MODEST A Ulrich 943 



ur views, the first of the natural !/.<, the others .2, of the slllclfled type of 

 this species. The peripheral wrinkles shown In figure 10 may have extended 

 all around originally. Stones River group, Murfreesboro, Tenn. 



Figs. 18 to 20 lUriii-niMiNA LAIMCIDA Salter sp 942 



18 Umbilical side of a large specimen, the apertural portion restored In the figure. 



Black River group, near Lebanon, Tennessee. 



19 Upper side of another specimen, from the same locality. 



20 Apertural view, with the apical whorls restored, of a third specimen, from the 



same locality. 



Figs. 21 to 23 RAPIUCTOMINA DKXTICULATA Ulrlch 943 



21 and 22 Two views of a coarsely slllclfled shell of this species. The surface markings 

 are very obscure except on a small portion of the upper part nf (Inure 22 

 where the deotlculatlons of the periphery also are shown. Black River group. 

 M.-rrer county, Kentucky. 



23 Dorsal view of a partial cast of the Interior from the same locality, showing 

 t h. obscure ridge beneath the peripheral an:le. 



Fig*. 24 to 29 LiosrtKA MH i \ II ill up MM 



24 u 26 Thre- a large and nearly perfect example of this species. L'tlca group, 



Covliik't.iri. Kentucky. 



27 Portion of tli.-iiml'T side of Ban >wlng surface markings and lower prt 



of peripheral band. The portion of tb. \posed In this view Is very 



n.ir 



28 Portion f upper >ide of last wborl of same, x5, showing delicate lln<- of 



tfrowth, th.- l.roa.l and faintly defined peripheral band, and obscure revolving 

 lines on the .ch revolving lines often extend over the whole u; 



side of the whorl*. 



29 Peripheral portion of preceding more highly magnified (vlO) giving an Idea of 



ih< eiceedlng delicacy of the marking*. 



