PLATE ILI. 
Mipiad.) BERENICHA EMINNESOTENSIS: Ults. 25226 -sscises «ae cicem ewe meelmiommtentiestsyse esti ritatate 120 
Small portion of the original of plate I, fig. 27, x18, showing zocecial apertures less con- 
stricted than usual, and portions of two non-celluliferous spots, 
. 
Figs. 2and 3. DIASTOPORINA FLABELLATA UlT...... 2.2. 0c ccse cece re nce e ere cect reerssccreserasees 122 
A complete zearium of this species, of the natural size and 7, showing arrangement of 
zocecial apertures, fine interstitial striae, and obscure concentric wrinkles. A small 
tubieulous annelid is attached to the frond. Upper part of the Galena shales at Can- 
non Falls, Minn. 
3. Portion of same X18, to show the characters of the species more clearly. 
Migs 4 CoG: SMIro Crm NA: |(?) MOUND UME WT. 5.00 55 /ere tor cs atieler acevo] ohetepatsy steve lnlalexe1s)aYa)etel«|ajpllv\nieletnlere/stebeta|«i-leisie 123 
4and5. Two fragments, nat. size and * 9. 
6. Original of fig. 5, <18. 
Upper part of the Galena shales at Cannon Falls, Minn. - 
Fig. 7. ARTHROCLEMA BILLINGSI Ulr.................. Reed gh te ca nue ete weit cia oaks Sos tole ee ee peters 197 
View of the type of this species, natural size. (Introduced to show mode of growth pre- 
vailing in this genus.) ve 
Trenton limestone, Ottawa, Can. 
RSS Subs 2b, -andu2s TOS. AR TARO OGLE MA ACR MCAUT Tia MN se ete ope tatetealeyotct oye ietebs (etc atet atta sheratatetstoisters 201 
8. Large segment of the primary series, showing a sharply defined articulating socket; nat- 
ural size and X18. This figure was inadvertently placed upside down. 
9. Opposite side of another segment of the primary set, x18. This and the preceding 
specimen is as thick as any noticed but not as long. 
10. Complete segment of the secondary set, 18. - 
11. Upper three fifths of another secondary segment, finely preserved, X18. Upper part of 
the Galena shales near Cannon Falls, Minn. 
25. Vertical section, X25, of a primary segment somewhat doubtfally referred to this species. 
Upper third of the Trenton shales, St. Paul, Minn. 
28. Transverse section of a small segment (?secondary) 25. Cannon Falls, Minn. 
29 and 30. Transverse and vertical sections of small segments found associated with the 
original of fig. 25. 
31 and 32. A transverse, and the lower half of a vertical section, *25, of full-grown primary. 
segments. Cannon Falls, Minn. 
33. Vertical section of a secondary segment, eqally enlarged and from the same horizon and 
locality as the preceding. 
Figs. 12 to 15. ARTHROCLEMA PULCHELLUM Billings...............0..--.eese-00s Je ncdogsaaoe so00 198 
12. Vertical section of secondary segment, *25. 
13. Transverse section of primary segment, 25, 
14and15 ‘Transverse sections, X25, of two secondary segments, one with six, the other 
with seven rows of zocecia. These sections were prepared from authentic examples : 
collected at Ottawa, Can., from the Trenton limestone. 
Migs 16ito;2l-andi23e) AR THRO CEMA (COR NUM AW per tetecetisteisise cieiesialel erie s/o leisiterstelersteteratere etelotsietsteisters 200 
16. A continuous series of four primary segments, natural size, and three of them 7, 
showing the articulating sockets near the base of each. 
17. A similar series of segments, consisting of seven of the secondary order, natural size, 
with flive of them *7. 
18 and 19. Two segments of the secondary order, X18, one with three cycles of zooscial aper- 
tures, the other with four. They differ also in the ornamentation. 
20 and 21. Opposite sides of rather small but very perfect primary segment, natural size 
and X18. (See also plate IIT.) 
23, Transverse section of primary segment, 18, showing five rows of zoccia. 
Middle third of the Trenton shales at Minneapolis, Minn. 
Figs. 22,and 24. ARTHROCLEMA STRIATUM, D. SP....-...ececceeececececss pee Pe ke cop a 198 
Tangential section, X28, and tranverse section, X18. (See also plate III.) 
ips 20/andi2y-) eARTHROGLENA ISD. NING Obiscmenceieeeisee en Meee eeRineen clon eiacinie ieee iiinesenieer: 203 
Two segments, the first incomplete, showing slight differences in ornamentation; *18. 
Trenton shales near Fountain, Minn. 
