PLATE LV. 



Trematopora (Orthopora) ornata. 



Page 1*4. 

 See Plate 56. 

 Fig. 1. An enlargement, showing the foi-m and disposition of the cell apertures and the character of the 

 interapertural space. (X 6 ) 



Hamilton group. Qenesea, N. Y. 



Trematopora (Orthopora) carinata. 



Page 179. 

 See Plate 56. 

 Fig. 2. An enlargement, showing the form and disposition of the cell a]>ertni-e3, the nodes between them, 

 and the prominent ridges sej>arating the ranges of a^Mirtures. (X 6.) 

 Hamilton group. West WUliains, Ontario, Canada. 



Trematopora (Orthopora) linkata. 



Page 181. 



See Plate 56. 



Fig. 3. An enlargement of a portion of a well-pi-eserved frond, showing the foi-m and arrangement of the 



cell aj)ertures, and the granulose ridges separating the range.s of apertures. (X 6.) 

 Fig. 4. An enlargement, showing the appeai-ance of a frond when macerated. (X 6.) 

 Fig. 5. An enlai-gement of a longitudinal section, showing the manner of gi-owth of the cell tubes, and 

 the intercellular space. (X 6.) 



Hamilton group IVest Hamburg, Krie county, N. Y. 

 Fig. 6. An enlargement of a portion of a sinuous frond having a greater number of ranges of apertures 

 than tig 3. (X 6.) 



Hamilton group. Ogdens Ferry, Cai/uga lake, N. Y. 



Acanthocle.ma sulcatum. 



Page IW. 

 See Plate 56. 

 Fig. 7. An enlargement, showing the form and ilispoeition of the cell apertures, and the sharply angular, 

 smooth ridges separating the ranges of apei-turea. 



Hamilton group. Oarien Centre, Qenesee county, iV. Y. 



Trematopora (Orthopora) hexagona. 



Page 173. 

 See Plate 56. 

 Fig. 8. An enlargement, showing the form and di.sjiosition of the cell apertures, and the appearance of 

 the interapertural space. (X 6.) 



Hamilton group. Bighteen-miU-ereek, Brie eminty, N. Y. 



Trematopora (Orthopora) reticulata. \ 



I'ago 179. 

 See Plate 56. 

 Fig. 9. An enlargement, showing the foi-m and arrangement of the cell apertui-ea, an<l the gi'aiiulose and 

 nodose interai>ertural 8)iace. (X 6.) ' 



Hamilton group. IVeitei-n New York. 



Trematopora (Orthopora) subquadrata. 



Page 177. 

 See Plate 56. 

 Fig. 10. An enlargroent, showing the form and disposition of the cell apertures, and the polygonal areas. 

 (X 6.) 



Hamilton group. Darien Centre, Qenesee county, N. Y. 



Trematopora (Orthopora) elo.voata. 



Page 183. 

 See Plate 56. 

 Fig. 11. An enlargement of a longitudinal section, showing the manner of gj-owth of the cell tubes, and 

 the intercellular space. (X 6.) 



Hamilton group. Oicasco Lake, N. Y. 



