EXPLANATION OF PLATE XV. 

 (All figures after Clark.) 



HEMIASTER PARASTATUS (Morton), p. 



1-4. Dorsal, ventral, lateral and posterior views of a complete 



individual. 



5. Anterior ambulacrum, enlarged. 



6-7. Portions of the petaloid and basal regions of the anterior 

 ambulacrum, much enlarged. 



8. Several plates from the petaloid region of the right antero- 



lateral ambulacrum, much enlarged. 



9. Three interambulacral plates with fasiole, enlarged. 

 10. Portion of fascicle, highly magnified. 



11-12. Two views of a tubercle, from the side and from above. 

 13. Apical disk, enlarged. 



Vincent own limesand. 



910 



