XVIII LIST OF ILLUSTRATIONS. 



Page. 

 Fig. 175. Hemiphragma glabrum. a and h, two fragments, natural size; 



c, basal portion of a zoarium, natural size; d, tangential section, 

 X 20; e, vertical section, X 20; /, several zooecia of a tangential 

 section, X 35 288 



176. Hemiplu'agma pygmseum. a, side view of a typical specimen, X 2; 



6, an ordinary tangential section, X 20; c, portion of the same, X 35; 



d, vertical section, X 20 289 



177. Hemiphragma multiporatum. a, side view of the type-specimen; 



6, tangential section, X 8; c, portion of the same, X 20; d, vertical 

 section, X 20, including a macula; e, a part of the same sec- 

 tion, X 20 291 



178. Hemiphragma subsphericum. a and 6, two portions of a tangential 



section, X 20 and X 8, in each case cutting a macula; c, zooecia of 

 the same section, X 40; d, vertical section, X 8; e, part of the 

 same section, X 20 292 



179. Hemiphragma subsphericum. a to d, four views of zoaria, natural 



size 293 



180. Hemiphragma rotundatum. a, side view of the type-specimen, 



natural size; fe, tangential section of the type, X 20; c, a vertical 

 section, X 20, illustrating the tabulation of both zooecia and 

 mesopores; d, a few zooecia, X 35 294 



181. Hemiphragma maculatum. a, a fragment, X 2, exhibiting portions 



of two maculae; 6, tangential section, X 20, through the inter- 

 macular zooecia; c, several zooecia of the same section, X 40; d, 

 vertical section, X 20 296 



182. Hemiphragma batheri. a and 6, two fragments, natural size; c, a 



tangential section, X 20; d, vertical section of a branch, X 20 297 



183. Anaphragma mirabile. a, view of branch, natural size; h, tangential 



section, X 20; c, several zooecia of another part of this section, X 20; 

 d, a vertical section, X 9; e, portion of the same section, X 20, 

 showing the structure in more detail 298 



184. Anaphragma mirabile cognata. a, view of fragment, natural size; h, 



tangential section, X 20; c and J, vertical section, X 8, and a por- 

 tion, X 20 300 



185. Dittopora clavaeformis. a, tangential section, X 20; h, vertical sec- 



tion of the same specimen, X 20 303 



186. Dittopora annulata. Copy of Eichwald's illustrations of Chaetetes 



annulatus. a, fragment of a normal mature zoarium, natural size; 

 fe, small portion of the same magnified; c, end view of a fragment en- 

 larged ; d, view of cells in section ; e and/, fragment of an old example 

 and a portion enlarged; g, end view of branch, magnified 304 



187. Dittopora annulata. a, tangential section of a mature example, X 20, 



passing through the outer deposit of interzooecial tissue in which 

 the mesopores are barely visible; h, another tangential section, 

 X 20, cutting a macula at a lower level and exhibiting the meso- 

 pores; c, vertical section, X 20, of a young example, showing the 

 occurrence of semidiaphragms in the bend from the immature to the 

 matm'e region; d, similar section of an older specimen, X 20, with 

 the mesopores well developed and their outer portions filled by 

 tissue 305 



188. Dittopora colliculata. Eichwald's figures of Trematopora colli- 



culata. a and 6, fragment of zoarium, natural size, and surface of 

 same, enlarged 306 



