PLATE II. 



PAGE. 



t ig. 1. BERENICEA MINNESOTENSIS Ulr 120 



Small portion of the original of plate I, flg. 27, x]8, showing zocscial apertures less con- 

 stricted than usual, and portions of two non-celluliferous spots, 



Figs.2and3. DIASTOPOKINA FLABELLATA Ulr 122 



A complete zoarium of this species, of the natural size and X7, showing arrangement of 

 zooecial apertures, fine interstitial strias, and obscure concentric wrinkles. A small 

 tubiculous annelid is attached to the frond. Upper part of the Galena shales at Can- 

 non Falls, Minn. 

 3. Portion of same xis, to show the characters of the species more clearly. 



Figs. 4 to 6. MITOCLEJIA (?) MUNDULUM Ulr 123 



4 and 5. Two fragments, nat. size and > 9. 

 6. Original of flg. 5, *18. 



Upper part of the Galena shales at Cannon Falls, Minn. 



Fig. 7. ARTHKOCLEMA BILLINGSI Ulr J97 



View of the type of this species, natural size. (Introduced to show mode of growth pre- 

 vailing in this genus.) 

 Trenton limestone, Ottawa, Can. 



Figs. 8 to 11, 25, and 28 to 33. ARTHROCLEMA AUMATUJI Ulr 201 



8. Large segment of the primary series, showing a sharply defined articulating socket; nat- 



ural size and xis. This figure was inadvertently placed upside down. 



9. Opposite side of another segment of the primary set, xis. This and the preceding 



specimen is as thick as any noticed but not as long. 



10. Complete segment of the secondary set, xis. 



11. Upper three fifths of another secondary segment, finely preserved, xis. Upper part of 



the Galena shales near Cannon Falls, Minn. 

 25. Vertical section, X25, of a primary segment somewhat doubtfully referred to this species. 



Upper third of the Trenton shales, St. Paul, Minn. 



28. Transverse section of a small segment ('secondary) X25. Cannon Falls, Minn. 

 29 and 30. Transverse and vertical sections of small segments found associated with the 



original of flg. 25. 

 31 and 32. A transverse, and the lower half of a vertical section, X25, 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 198 



12. Vertical section of secondary segment, X25. 



13. Transverse section of primary segment, X25. 



14 and 15 Transverse sections, X25, of two secondary segments, one with six, the other 

 with seven rows of zooecia. These sections were prepared from authentic examples 

 collected at Ottawa, Can., from the Trenton limestone. 



Figs. 16 to 21 and 23. ARTHROCLEMA CORNUTUM Ulr 200 



16. A continuous series of four primary segments, natural size, and three of them XT, 



showing the articulating sockets near the base of each. 

 IT. A similar series of segments, consisting of seven of the secondary order, natural size, 



with flive of them XT. 

 18 and 19. Two segments of the secondary order, xis, one with three cycles of zooecial 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 xis. (See also plate III.) 



23. Transverse section of primary segment, xis, showing five rows of zooacia. 

 Middle third of the Trenton shales at Minneapolis, Minn. 



Figs. 22 and 24. ARTHROCLEMA STRIATTJM, n. sp 198 



Tangential section, X28, and tran verse section, xjg. (See also plate III.) 



Figs. 26 and 2T. ARTHROCLEMA sp. undet 203 



Two segments, the first incomplete, showing slight differences in ornamentation; xis. 

 Trenton shales near Fountain, Minn. 



