﻿ulrich-bassler] revision of paleozoic bryozoa 53 



8. A portion of the same, X 50. 



Richmond formation, Versailles, Indiana. 



I 1 !. ATE X 



Stigmatella nicklesi new species. (See also plate xiv, 9, to)... .p. 36 

 Fig. 1. Vertical section, X 20. The lower curved line represents the outer 

 surface of the crinoid stem over which the colony has grown, 

 while the shaded portion above it represents a clay-filled intei 

 space. 



2. Tangential section, X 20, showing the very large and sharply 



defined acanthopores and thin zocecial walls. 



3. Several zooecia of the same section, X 50. 



Fairmount beds, Lorraine formation, Cincinnati, Ohio. 



Stigmatella clavis ( Id rich ) p. 34 



4. Tangential section of several zooecia, X 50. Introduced for com- 



parison with 5". nicklesi. 



Lower beds of Utica formation, Covington, Kentucky. 

 Stigmatella irregularis (Ulrich). (See also plate xiv, 6-8) p. 34 



5. Vertical section, X 20, illustrating the periodical development of 



the acanthopores and the extreme infrequency of the dia- 

 phragms. 



6. Small part of a tangential section, X 40, where it passes through 



one of the zones of acanthopores. Ordinarily tangential sec- 

 tions show no acanthopores. 



Fairmount beds, Lorraine formation, Hamilton, Ohio. 

 Stigmatella nana new species. (See also plate xiv, 11, 12) p. 36 



7. Ordinary aspect of tangential sections, X 20. 



8. Portion of same, X 50. 



9, 10. Vertical section, X 20, and portion of same, X 40. 



Utica formation, West Covington, Kentucky. 



Stigmatella dychei (James) P- 34 



11. Vertical section, X 10, showing adaptation of zoarium to irregu- 

 larity of the object grown upon. 



Mt. Auburn beds of Lorraine formation, Lebanon, Ohio. 



Plate XI 



Heterotrypa frondosa (D'Orbigny) p. -5 



Figs, i, 2. Tangential sections, X 35 and X 20, illustrating the wall structure 

 and the distribution and character of the acanthopores and 

 mesopores. 

 3. Vertical section, X 20, exhibiting the tabulation of zooecia and 

 mesopores. 



Sections prepared from the original of Edwards and Haime's 



figures of the species. 

 Lorraine formation, Cincinnati, Ohio. 



Heterotrypa parvulipora new species p. 26 



4, 5. Vertical and tangential sections, X20. The almost total absence 

 of mesopores is a noteworthy characteristic of this species. 

 6. A single zocecium, X 50, exhibiting the wall structure and acan- 

 thopores. 

 6 



