PLATE III. 
PAGE. 
Hae. Eb K ONKOL. G inne ware UNS Olean gondonagnes cagento gas so oco0s ceno orp anton bondoste dese 191 
1. A segment of the natural size and <7, Minneapolis. Minn. 
2. Portion of same, x18. Only three of the four rows of zocecia to be seen in this view have 
. been drawn. 
3. Transeverse section, X18, showing a spiral development of the zoocia. 
Lower third of the Trenton shales at Minneapolis, Minn. 
NS 406 wee OPO R ANSP INTRO RMTS MU UAetot ote tetetete\eletorete ievele etene tate tenetnietedel metstatenete rates ie ieiallotele (ele taladatefera ctl Te 190 
4. A segment natural size, and lower portion of same 18. 
5and 6. Vertical and transverse sections, *18. 
“Glade” limestone at Lavergue, Tenn. 
TOMES Ul Nis Koforoy oe eA ON en PO MPa nag. Sodan seaddoonaeambosaccusonao sa Goo pbb op Shoo goMEnmoaTOOSoc 201 
A small segment supposed to belong to the tertiary set of this species, x18. Cannon 
Falls, Minn. (See also plate II.) 
dts ts Lehpioutory A (Digi wleGllis poe Gone nodsboddonosos sposasaob sponds Hons Andes Dodo sconcaepnaee NT O04 196 
Nearly entire segment, X18. Upper part of Galena shales, near Cannon Falls, Minn. 
JOSS Wh, MEH E ONO uch wore YN Ollie g or ono ac aocUuGeo spondooanbboocoosdon ws Hb oapecsspostapongsbadnds > 192 
About three fourths of a segment of this species, x18. Middle third of the Trenton 
shales, Minneapolis, Minn. Itis within the possibilities that these segments may 
belong to the tertiary set of Arthroclema striatum Ul. 
i oe OSE OR OR AWMU CR ONUAUA Sy UIT etere reteset a atemete re totet ie ieletyatetce fects lohn/olaperstetcfemeiet= aicietetsieheteleleleleae aicls/alel-yetaiare 193 
A segment of this form natural size, and the greater ‘part of it x18. The specimens 
upon which this species is found may prove to belong to Arthroclema armatum Ulr. 
Upper part of Galena shales, near Cannon Falls, Minn. 
Migs WG bOM ey EET O POR ACCA RIS 1 i ALN CS ie terererctoyeterstefeletsietevsvevelere iets tate totes telaobetersttetomelaleletivetatel=,ctefoyiaia(aleteierats 195 
ll and 12. Two segments, natural size and X18. 
lla. Portion of original of fig. 11, x50. 
11b. Transverse section of a segment, X50. 
Hudson River group, Waynesville, Ohio. 
Figs. 13 and 14. ARTHROSYLUS CONJUNCTUS Ulr...... 0.6.23. cece cece tence Brae oral Yaseseses ee av eneseee b 188 
13. Lateral view of the central portion of a segment, “18. s 
14. View of small portion of non-celluliferous side of same, *18. 
Trenton shales, near Fountain, Minn. 
Mics el bland eG ee ARTE OST US OB TLE) UU pm) Ui stavererey-fekede retell steiateisenettstetetertaeiaieteltotetteratatateietctoteioneteleteantetela 188 
Two views of a segment of this species, X18, in the first showing the non-celluliferous 
side with the upper extremity and about three-fourths of the length, in the second 
the central portion turned so as to show the lateral aspect. 
Lower third of the Trenton shales at Minneapolis, Minn. 
Beneath fig. 15 a small figure is erroneously marked with the number 16. This repre- 
sents a transverse section of the type of the genus A. tenwis (James), from the lower 
part of the rocks at Cincinnati, Ohio. 
igs iho 20s) ONE NCA TOP ORIA GGHVAN OSA SIUM ocjerstes morete east ited itera telat ie creicvelere fusiols lene iste aieyeltaiet are ete 205 
17. Portion of unbranched fragment, *18, showing the granulose angles and interspaces, 
and narrow zocecial apertures; the latter i in five rows. 
18. Bifurcating fragment, *18, with the rows of granules slightly flexuous. 
19 and 20. Portion of slightly worn fragment, and end view of same, *18. This has only 
four rows of zooecia. 
Upper part of Galena sbales, near Cannon Falls, Minn. 
NOS 22160 2osey INEINCALTO POR AU CONTE: Aa Ollie tate fe cteneyeitlatereleeloterarheieletemateyerale otek attelolatetetepaietele ere leliet=te otatelststets 206 
Zoarium of this species, natural size, <9, and portion of same *18. Upper part of Galena 
shales, near Cannon Falls, Minn. 
MCS p24 Anya). peNIEE MAC OP ORAS Oj VPAIETS AU) Ilveeanelotreetar tated ott tetete bets reretere teteteyet-teteretalal stole scott jelerstatetierey sts tar teke iene toe ke 204 
Two fragments of this opecies, natural size and x18, the first with four rows of zooecia, 
the other with five. Upper part of Galena shales, near Cannon Falls, Minn. 
Wigs s2Grandi2h NEMA ORO R ANI HIG LC AT OIG Wii terorete Metety slate ajeletelelorolalelalaleratsleielelestsieleteteierst= eiciatel teietal eietaeeys 206 
Two fragments of the exceedingly delicate zoarium of this species, natural size and 
x18. Upper part of Galena shales, near Cannon Falls, Minn. 
Migs 28ib0ido. CAR LOR OCLE MAL SUR LAM UIMarI iS]: 5 tersvelejalerstetetsazelelsreiieteverelcte sielotere miisrsinieretetestecel sterafetatetareserots(ateiy 198 
28. Puma segment, natural size and X12, with a large articulating socket and expanding 
ends. 
29. Lower end of same, X18. 
30 and 31. Lateral and end views of a large and strongly striated primary segment, natural 
size and X18. The zoocecial apertures are incorrectly represented in this figure. (See 
correction p. 199, sixth line from top.) 
32 and 33. Two segments of the secondary set, natural size and X18. One has five cycles of 
zoccia and an articulating socket, the other six cycles and no distinguishable socket. 
(See also plate IT.) 
Middle third of the Trenton shales, Minneapolis, Minn. 
Higstot, GARTHROCL EMA: CORN UM UMW llietrartstsrstetcione siete! ele relelaletsletalensiereieloustetete lalate: «femtin dere voletate temas iaseiehel tates tere 200 
‘View of upper end of the segment represented by fig. 18 on plate II; x18. 
Figs. 35 to 37. ARTHROCLEMA, Sp. undet............cceeee eens ronondEoadsde Usgamidy SobpcbboO bean ode 203 
35. Slightly abraded segment, natural size and X18. An obscure, subcentrally situated, 
articulating socket is distinguishable. 
36 and 37. aye internal casts of the zooscia, X18, showing their spiral arrangement in the 
segmen 
Uiper third of the Trenton shales, St. Paul, Minn. 
