Fig. 110. Cidaris papillata Leske, Section of a pyramid with its tooth; in 



this and foUowing figures X the rough area and + tlie fibrous tissue. 

 Fig. 111. The dental slide -with the two »lineae eminentes» Val. 

 Fig. 112. A tooth, side-view. 

 Fig. 113. The half of the alveolar cavity. 

 Fig. 114. Discoidea ctjlindrica, Lamck. The dental slide. 

 Fig. llö. The half of the alveolar cavity. 



Fig. IIG. AstJienosoma rariuni, Grube. Section of a pyramid with its tooth. 

 Fig. 117. Tooth seen from the side and from behind. 

 Fig. 118. The half of the alveolar cavity. 



Fig. 119. Diadema saxatile, L. Section of a pyramid with its tooth. 

 Fig. 120. Echinus esculentus, L. Section of a pyramid with its tooth. 

 Fig. 121. A tooth, side-view. 

 Fig. 122. The half of the alveolar cavity. 

 Fig. 123. The dental slide. 

 Fig. 124. A tooth, back view. 

 Fig. 12Ö. Section of a part of the pyramid at X and of the tooth, to show 



the fibrous tissue + that connects theni. 

 Fig. 12G. The structure of the rough area, magnified. 

 Fig. 127. The same, longitudinal section. 

 Fig. 128. The same, transverse section. 

 Fig. 129. The symphysis of the pyramid. 

 Fig. 130. Strongylocentrus lividus Lamck. Section of a pyramid with its 



tooth. 

 Fig. 131. Cli/peaster retiadatus L. Section of a ])yramid with its tooth. 

 Fig. 132. The dental slide; X the rough area. 

 Fig. loo. The tooth, back view; X the rough area. 

 Fig. 134. Section of a part of the pyramid aud of the tooth showing the 



extension of the rough area X and the fibrous tissue + . 

 Fig. 135. Echinarachnius parma, Lamck. Section of a pyramid with its 



tooth. The me.sial suture is serrated ; X X the compacted tissue 



ending in the j>triangle». 

 Fig. 136. Section showing the extension of the fibrous tissue and the mesial 



suture; X and + as above. 

 Fig. 137. The dental slide. 

 Fig. 138. A tooth, back view area. 

 Fig. 139. Lagannm decagonale, Bly. Section of a pyramid with its tooth. 



