Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Fig. 
Figs. 30 and 31. 
Figs. 32 and 33. 
Fig. 
1 and 2. 
3 and 4. 
5 and 6. 
12 to 
15 and 
17 _ to 
20 to 
20 to 
25 to 
14, 
a 
16. 
19, 
34. 
PLATE XXXVII. 
ENDODESMA ORTHONOTUM Meek and Worthen, Sp....-.--+--++2+eee ec ceee cee eeeee 
Lateral and dorsal views of the original type of this species. The specimen is a 
good cast of the interior, in solid limestone, of a left valve. All of it is now 
exposed, the tough matrix, which covered a considerable portion of the ventral 
margin when it was used by Meek and Worthen, having been removed before 
it was redrawn for the present work. Lower Trenton limestone, Dunleith, 
Illinois. 
ENDODESMA GESNERI Billings, sp...........- PROD TAO ite BODO artis OCCA EODOS 
Lateral and dorsal views of a good cast of the interior of a right valve. Trenton 
limestone, Ottawa, Canada. Introduced for comparison with the other species 
of this proposed genus. 3 
ENDODESMA POSTLATUM, Do SDP ccc cece wien ccc ce core ve ccma oo ene eee assem = elelsleee 
Lateral and dorsal views of an internal cast. Upper Galena, Dubuque, Iowa. 
Geol. Survey Museum Reg. No. 8345. 
ORTHODESMA CANALICULATUM, DN. SDP.....---- Be cantb pdocatros 2G Sacto neta 
The right side and a dorsal view of a nearly entire cast. Waynesville, Ohio. 
Well preserved but incomplete cast, showing the anterior end and obscure rays 
across the central half. Upper beds of the Cincinnati group, Waynesville, Ohio. | 
Posterior two-thirds of a cast from the Hudson River group near Spring Valley, 
Minnesota. The length of this specimen was reduced by pressure, and to this 
cause we must ascribe the more crowded arrangement of the radiating lines. 
View of the broken end of same, showing the natural convexity of the valves 
and the cardinal depression. 
ORTHODESMA MINNESOTENSE Ulrich 
The left side of the type specimen. 
Dorsal view of same. - 
Anterior part of a dorsal view, x 4. Middle third of the Trenton shales, Minne- 
apolis, Minnesota. 
MODIOLOPSIS CONCENTRICA Hall and Whitfield. ...............-.. ee cece seeeeeeees 
SET of the shell as obtained from a gutta-percha impression of a natural 
mold. 
Finely preserved cast of the interior. In offering these figures I wish it to be 
understood that the specimens selected are strictly normal for the species as 
it occurs in Ohio. Further, that the species is very constant, and that all 
marked deviations in contour which may be observed in a series of specimens 
are the result of distortion through pressure. 
VANUXEMIA SARDESONI Ulrich 
(See also plate xxxviul, fig. 45.) 
Lateral, anterior and cardinal views of the best cast seen. Trenton limestone, 
Minneapolis, Minnesota. 
MODIOLODON PATUIUS; We Spi ieieteicrets sie wictato!ata)eie ofa !e)@celelotetslafots i=] otet=t>tos 2) ein in teivhe elaleiajos are 
The left side and anterior and dorsal views of a cast. Lower or middle Galena, 
Decorah, Iowa. Geol. Sur. Mus. Reg. No. 8363. 
The left side of a cast of the interior from the Trenton at Danville, Kentucky. 
A small specimen from the middle Galena of Goodhue county, Minnesota. 
@LENODONTA PLANODORSATA UWITICH <..20re cee eee twee cca ewe weiner cin sme ese ds 
(See also plate xuit. figs. 38 to 40.) 
Posterior view of the original type. : 
Right valve of same, with a small part of the surface magnified. « 
Profile in a postero-basal view. 
Cardinal view of same. Upper part of middle third of Trenton shales, Goodhue 
county, Minnesota. 
CLENODONTA/COMPRESSIA, TOUTE G Here. areise, caivi ote nlels!aicie o.ole)sileretels a /olaicistaiarein! wiataialbre/alaistelets 
ee (See also plate XLIt, figs. 88 to 90.) 
The original type of the species, x 1.3. Upper part of the middle third of the 
Trenton shales, Goodhue county, Minnesota. 
CLRENODONTARSTONGEAS WITICHE sar ches sis ore ercre = aces oxo pevaleeta ee letonite ei ste tenets feretoierete siete iia iaters 
Interior of the right valve upon which this species was founded, magnified twice 
and of the natural size. Middle third of the Trenton shales, Goodhue county, 
Minnesota. 
GLIDOPHORUS  P.CONSUB TUS: WLI CIs «crs; 0sa:0,<.011ccesei =) wlelerelmietayolerclale arias alee tadeisieos lanel<tslle t= ose 
The type specimen of the natural size and magnified twice. Middle Galena near 
Wykoff, Minnesota. 
TECHNOPHORUS EXTENUATUS UIrich.........cccscecsccceccnne eeeceeees  veeees 
View of the left side of the cast of the interior upon which the species was 
founded. Middle third of the Trenton shales, Minneapolis, Minnesota. 
528 
527 
520 
517 
510 
555 
589 
600 
590 
606 
614 
