PLATE XI«. 



Clypeaster humilis, f. 1-8. 



1. The five jaws seen from abactinal side. 



2. Same seen in pi'ofile. 



3. Same seen from the actinal side. 



4. One of the jaws in profile. 



5. One of the jaws seen from the centre of mouth. 



6. One of the jaws seen endwise. 



7. Single lateral jaw seen from the actinal side. 



8. The odd jaw seen from the actinal side. 



Echinodiscus auritus, f. 9-13. 



9. The five jaws seen from the abactinal side. 



10. Same seen from the actinal side. 



11. Single jaw seen from the actinal side. 



1 2. Single jaw seen in profile. 



13. Single jaw seen from the abactinal side. 



{All jigs, natural size.) 



