PLATE XXVII. 



PAGE. 



Figs. 1 to 8. BATOSTOMA WINCIIELLI Ulr 295 



1, 2 and 3. Vertical sections xis, of a young, medium, and an old specimen. 



4 and 5. Tangential section, xis and xso, of the same specimen from which was prepared 



the vertical section shown in flg. 3. 

 6. Tangential section of a young specimen xis. 



7 and 8. Tangential section of the var spinulosum xis and x50. (See also plate 26.) 

 Middle third of the Trenton shales, Minneapolis and St. Paul. 



Figs. 9 to 15. BATOSTOMA MINNESOTENSE, n. sp 297 



9 and 10. Portions of a tangential section xis and xso. 



1 1 and 12. Peripheral and axial regions of a vertical section prepared from the same speci- 

 men as the preceding, xis. 

 13. The peripheral part of a zooecial tube with fewer diaphragms than usual, x is. The true 



average for the species is intermediate between this and flg. 11. 



14 and 15. Portions of two tangential sections, xis and xso, in a different state of preser- 

 vation than flgs. 9 and 10. (See also plate 26.) 

 Middle third of the Trenton shales, St. Paul and Minneapolis. 



Figs. 16 to 19. BATOSTOMA (?) DECIPIENS, n. sp 298 



16. Small portion of a vertical section xis. 



17 and 18. Tangential section xis and xso. In some parts of this section certain small 



acanthopore-like dots are distinguishable usually about midway between the angles. 



They are dark and scarcely half the size of the smallest shown in flg. 10. 



19. From the axial region of a transverse section xis. 

 Lower half of the Trenton shales, Minneapolis. 



Figs. 20 and 21 . LEPTOTRYPA CLAVIFORMIS, n. sp 319 



20. Tangential section xis. In this section the cells here drawn as open are tilled with 



matrix, while those shaded are occupied by clear calcite. The smaller of the latter 

 have the appearance of mesopores; on the other hand, since the preservation of the 

 fossil is not favorable, it is possible that they represent acanthopores. 



21. Vertical section of the upper extremity of same beyond the foreign body, xis. 

 Middle third of the Trenton shales, St. Paul. 



Figs. 22 and 23. LEPTOTRYPA INFORMIS, n. sp . . 317 



Tangential and vertical sections xis. 



Lower third of the Trenton shales, Minneapolis. 



Figs. 24 and 25. LEPTOTRYPA ACERVULOSA, n. sp 318 



Tangential and vertical sections xis. 

 Galena shales, Decorah, Iowa. 



Figs. 26 and 27. MONOTRYPA (?CH,ETETES) CUMULATA, n. sp 307 



Tangential and vertical sections xg. Beneath the first the structure of the wall is shown xss. 

 Upper part of the Galena shales, Goodhue county, Minn . 



Figs. 28 and 29. MONOTRYPA MAGJJA, n. sp 304 



Vertical and tangential sections xg. 



"Lower Blue" limestone at Dixon, 111. 



