PLATE LIX. 



Figs. 1-5. Baihydorus stellatus, F. E. S., 



Fig. 1. A somewhat damaged s^Jecimen, preserved in alcohol ; natural size. 



Fig. 2. Oxyhexaster, whose princi^^al rays are aborted ; x 300. 



Fig. 3. Great autodermal tetract with straight, rounded, rough rays ; x 300. 



Fig. 4. Small discohexaster ; x 300. 



Fig. 5. Autodermal rough diact with an annular central thickening and rounded 

 ends ; x 300. 



Figs. 6-9. Bathydonis spinosus, F. E. S., 

 Fig. 6. Inferiorly damaged specimen, preserved in alcohol ; natural size. 

 Fig. 7. Oxyhexact with straight, smooth, pointed rays ; x 300. 

 Fig. 8. Oxyhexaster with S-like terminal rays ; x 300. 

 Fig. 9. Oxyhexaster with irregularly bent terminal rays ; x 300. 



Figs. 10-18. Bathydorus haculifer, F. E. S., 

 Fig. 10. A fragment; natural size. 

 Fig. 11. Dermal skeleton, in natural position ; x 50. 

 Figs. 12, 13. Oxyhexasters with bent terminal rays; x 300. 



Fig. 14. Monact with five rough knobs at the blunt (central) end, and a straight, 

 rough, rounded ray ; x 300. 



Fig. 15. Straight diact with two rough central knobs, and rough obtuse rays; 

 X 300. 



Fig. 16. Angular diact with central knot, and straight rough rays ; x 300. 



Fig. 17. Straight diact with central knot, and rough obtuse rays ; x 300. 



Fig. 18. Discohexaster; x 300. 



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