PLATE XVIII. 
rage. 
Fig. 1. Clarkia myiformis, J. D. Dana — Portion of valve, with shell ... ... ... 209 
Fig. la. Internal cast of the right valve ... ... ... ... ..-t ... ... 209 
Fig. U. The same, seen from above, to show the tooth with which the hinge is provided 209 
Fig. 2. Cardinia exilis, F. McCoy — Lateral view of specimen ... ... ... ... 213 
Fig. 2a. The same, seen from above ... ... ... ... ... ... ... ... 213 
Fig. 3. Udmondia .f sfi'iatocostata, ¥. McCoy — External impression of the valves ... 211 
Fig. 4. Cardiomorplia? gryphioides, L. Gr. de T-Coninck — Internal cast, seen in profile ... 210 
Fig. 5. Pachydomus glohosus, J . T). ^ovfcvhj — Lateral view of specimen ... ... 214 
Fig. 5a. The same, seen from above ... ... ... ... ... ... ... ... 214 
Fig. 0. PacJiydomus cypri/ia, J. D. — Internal cast, side view ... ... ... 217 
Fig. 6a. The same, seen from above ... ... ... ... ... ... ... ... 217 
