ORGANIC DEPENDENCE AND DISEASE 79 
ties of their observation occurs on no other crinoid species 
except Scytalocrinus robustus, which also possesses a long 
anal tube but with the aperture far down toward the base 
and within easy reach of the starfish. We here illus- 
trate a Barycrinus ( B . Hoveyi Hall), a species without 
anal proboscis, engaged with this starfish. No evidence 
exists that this habitude continued beyond the Lower Car- 
boniferous. One familiar with the feeding habits of the 
starfish from ancient Devonian times to the present would 
be disposed to suggest that the association under present 
consideration can be only for feeding purposes. That this 
may have been “a favorite resting place” (Wachsmuth and 
Fig. 66. The crinoid Barycrinus Hoveyi with the starfish Onychaster Uexilis inter- 
twined with the arms. Mississippian. 
Springer) for the starfish will hardly explain it. The small 
boy in an apple tree is not there to rest. This affiliation, 
its constant recurrence always between the same species of 
starfish and a very few species of contemporary crinoids ; 
limited apparently to the very brief period which repre- 
