XIV LIST OF ILLUSTRATIONS. 



Page. 

 Fig. 109. Mesotrypa milleporacea. a, the epithecal side of a fragmentary zoa- 

 rium, natural size; b and c, a tangential section, X 20, and several 

 zooecia, X 35; d, tangential section of the same specimen, X 20; 

 e, vertical section, X 20 202 



110. Mesotrypa milleporacea parva. a, a zoarium, X 2; 6 and c, a tan- 



gential section, X 20, with several zooecia, X 35; d, vertical sec- 

 tion, X 20 203 



111. Dekayella pragnuntia and varieties, a, fragment of a variety, natu- 



ral size; h, tangential section, X 18, of the typical form; c, tan- 

 gential section, X 18, of variety simplex; d, and e, small portions 

 of two tangential sections, X 50; /, vertical section, X 9, of speci- 

 men with numerous mesopores; g, minute structure of walls in 

 ■ sections, X 50 206 



112. Leptoti-ypa hexagonalis. a, the original type of the species, natural 



size, incrusting a Hyolithes; b, surface of the same, X 32. (After 

 Ulrich.) c, a fragment of limestone with a Hyolithes incrusted by 

 this delicate bryozoan 208 



113. Leptotrypa hexagonalis. a, tangential section of the American type 



of the species, X 20; b, several zooecia of the same section, X 30; 



c, vertical section, X 20 209 



114. Leptotrypa hexagonalis. a, tangential section, X 20; of a Russian 



example; b, vertical section, X 20; c, a vertical section, X 20; d, 

 tangential section, X 20 209 



115. Stigmatella massalis. a, side view of the type-specimen, natural 



size; b and c, tangential section, X 20, and a portion of the same, 

 X 35; d, vertical section, X 8; e, portion of the same section, X 20; 

 /, part of vertical section, X 20, through a macula 211 



116. Stigmatella inflecta. a, side view of the type-specimen, natiiral size; 



b, tangential section, X 20; c, another tangential section, X 20; 



d, several zooecia of the same section, X 40; e, vertical section, 



X 20 213 



117. Stigmatella foordii. a, a large specimen of Callopora foordii, of the 



natural size; b, tangential section of the same; c, vertical section 



of the same. (After Nicholson.) 215 



118. Stigmatella foordii. a, vertical section, X 20; b, tangential section 



X 20; c, portion of the same section, X 35; d, another portion, 



X 35; e, several zooecia of a tangential section, X 50 216 



119. Stigmatella claviformis. a and b, two of the club-shaped zoaria, nat- 



ural size; c, view of zooecia in tangential section, X 18; d, vertical 

 section tlirough the middle of a zoaiium, X 18. (After Ulrich.). . 217 



120. Constellaria varia. a, fragment of a zoarium, natiural size; b, surface 



of a mature specimen, X 9; c, tangential section, X 18; d, small 

 portion of the same, X 50, with two mural tubuli; e, vertical sec- 

 tion of average example, X 18. (After Ulrich.) 219 



121. Constellaria varia. a, tangential section, X 20, cutting several rays 



of a macula; b, vertical section, X 20, passing through a macula. . 220 



122. Constellaria varia. a, vertical section, X 20, of a small example; 6, 



transverse section of the same specimen, X 20 220 



123. Stellipora revalensis. a, vertical section, X 20; b, tangential sec- 



tion, X 20, illustrating structure of two rays of a cluster 222 



124. Stellipora apsendesoides. A zoarium, X 3, attached to a specimen 



of Echinospherites 223 



125. Nicholsonella gibbosa. Eichwald's figures of Heteropora gibbosa; 



a, zoarium, natural size; b, the surface enlai'ged 225 



