PLATE XIII. 
PENTACRINUS ASTERIUS, Linn., sp. 
Diam. , Page 
Fig. 1. The calyx and arm-bases, . : ‘ : 5 Bote eae 300 
Figs. 2-4. A nodal joint from the upper part of the stem. 
Fig. 2. Upper face, . : : : : : =e SB 17 
Fig. 3. Lower face, . ; : ; : : cere et 17 
Fig. 4. Side view, . ; : : : , a> eee 14 
Fig. 5. A nodal joint from the lower part of the stem; lower face, . x 4 ive 
Fig. 6. The same ; upper face, : : : : ‘sXe ee 17 
Fig. 7. Portion of an internode from near the top of the stem, me fe 18 
Fig. 8. Nodal and internodal joints from the lower part of the stem,. x 2 305 
Fig. 9. Face of a young internodal joint, —. : : se BCH hoe 15 
Figs. 10, 11. Faces of older internodal joints, . BN OC a at 17 
Fig. 12. Terminal face of a pinnule-joint, ; : FS ed 10 
Fig. 13. Termination of an arm, : aX 2 300 
Fig. 14. One of the middle arm-joints and its pinnule, : ss Ree 286 
Fig. 15. The ambulacral skeleton of an outer pinnule, eG i) 
Fig. 16. Ventral aspect of the basal joints of a lower pinnule, showing 
the development of its ambulacral skeleton, : - 1 & 20 79 
