EXPLANATION OF PLATE XVI. 

 (All figures after Clark.) 



HEMIASTER STELLA (Morton), .... .............. ..................... p. 300 



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

 individual. 



Vincent own lime sand. 



UNGULA (Morton), ...................................... p. 301 



5-8. Dorsal, ventral, lateral and posterior views of a complete 



individual. 

 9. Portion of the petaloid region of the right antero-latcral 



ambulacrum, much enlarged. 

 10. Portion of the petaloid region of the anterior ambulacrum, 



much enlarged. 

 IT. Apical disk, enlarged. 



Vincentotvn liniesand. 



912 



