PLATE LXII. 



I to 4 CABINAI:<>I'-I^ < \ MIH i \ II.iii ... 



l Dorsal view of a *i"' r >"" imi" i rfrri at the sides. 



S Diagramallc longltinlma! e<-tloii. The dott*l line represents th- ouillne of the 



lateral margins ID a profile 



Two views of a broken specimen showing the Internal st-ptum. 

 I'j.jier part of Trvnton group, near Danville, Kentucky. 



3 and 4 



IV 6 



-m KXTLANATA t'lrlch 9J9 



Dorsal rlew of the iiniv.-rf.-<-t type of tbla species. It Is a cant of the Interior. 

 Upper part of Trenton group, Qovlngton, K.-ntucky. 



Figa. ft to B CAUINAROPSIS ACUTA U. and S 028 



6 and 7 Doraal and profile views of a cut of the Interior of a young shell, black River 



group, near Fountain, Minnesota. 

 8 and View of the Interior of a very large example, and a diagrammatic longitudinal 



section of the same. Black River group, near Cannon Falls, Minnesota. 



fig*- 10 to 13 CARINAROPSU CUNULJC II all 927 



10 Doraal view of an average shell. The margin restored from other specimens. 



11 Diagrammatic longitudinal section of same showing outer surface only of the 



operculum (at "O"). 



12 Another specimen showing a sharply defined dorsal band. 



l.i IMII.T surface of original of figure 10, showing the septum and, above It. a triangu- 

 lar plate which we regard as the operculum. 

 Trenton group, Nashville, Tennessee. 



Figs. 14 to 18 CARiNAKOPtfix riiALEKA Sardeson 928 



14 A cant of the Interior of this species from the Otenodonta bed at St. Paul 

 1& Diagrammatic longitudinal section. 

 10 and 17 Interior and profile views of an Imperfect shell. 



18 A specimen broken so aa to show the Inner surface of the septum. This, like the 

 preceding, is from the Ctenodonta bed at Chatfleld, Minnesota. 



I 19 CARiNAKorsis MINIMA U. and S 929 



Dorsal view of the type and only known specimen of this species. Black River 

 group, Cannon Falls, Minnesota. 



Figs. 20 to 28 CTRTOLITBS(?) DILATATUS D. andS 885 



20 to 23 Four views of a large cast of the Interior, IMoit. Wisconsin. Collection of the 



I'nlveralty of Wisconsin. 

 24 to 26 Throe views of a smaller teatlferous example, from the Ctenodonta bed of the 



Black River group, near Gannon Falls, Minnesota. 



tigs. 27 to 29 CYRTOUTM ORNATUB Conrad 860 



27 Lateral view of a large specimen preserving Home of the shell. Thomirface orna- 



mentation Is loo delicate to b drawn of the natural sice, and only a few of the 

 transverse lines are represented In the figure to give an Idea of their direction. 

 Lorraine group, Cincinnati, Ohio. 



28 Small portion of the surface markings on the dorsal slopes of another specimen 



from the same locality, xlO. 



29 Dorsum of a third example, from the same locality, x<- . 



Figs. 30 and 31 CVBTOLITBS OBNATUS var. MINOR U. and S 891 



Lateral and dorsal views of a specimen of this variety, *.t. Clltambonltes bed of 

 the Trenton group, Cannon Falls, Minnesota. 



Figs. 32 to 31 CYRTOMTK." RarrRiOHSUS Ulrirh 861 



32 and 33 Two views of a large sillclfied example showing the usual character* of the species. 

 Th'- Backward sweep of the transverse markings on the doraum and the small 

 .ral fold are the principal distinctive features when compared with C. orna- 

 tut. Trenton group, Tennessee. 

 34 Surface of a specimen from Kentucky, xlO. 



36 to 37 Three views, x2, of a smaller sillclfied shell. Trenton group, Mercer county, 

 Kentucky. 



Fig*. Wand 39 CTRTOUTW RBTBOBSOS var KILLMORENMS u. an. I > 



38 One of the largeM. and best specimens of this variety soen. It Is chiefly a cati ' 



the Interior. Black River group, near Fountain, Minnesota. 



Tbe Inner whorls of another specimen from the same locality magnified (xlO) to 

 show their rounded sides and th- ornamentation. 



