PLATE V. 



Plumaster ophiuroides, Wriyht. 

 From the Middle Lias. 



1 a. Plumaster ophiuroides, Wright, p. 112. Ventral surface, natural size. 



b. Ambulacral and inter-ambulacral ossicula, magnified ; the long inter-ambulacral plates 



with pectinated distal borders supporting rows of spiniferous tubercles. 



c. A pair of large angle-plates with tubercles on their surface, magnified. 



LuiDiA Murchisoni, Williamson, 

 From the Middle Lias. 

 2. LuiDiA MuRCHisoMi, WHUamson, p. 111. Ventral surface, natural size. 



