78 
ORGANIC DEPENDENCE AND DISEASE 
parasitism continued. The habit was extinct; I think we 
may say that this particular adjustment had been extin- 
guished. 
SYMBIOTIC CONJUNCTION OF CRINOIDS AND 
STARFISHES 
This is a habitude which, so far as known, is exhibited 
only in the Mississippian fauna of the Lower Carbonifer- 
ous and on its face it would appear to be a purely voluntary 
association, as there is no anatomical evidence that the star- 
fish has sacrificed its locomotive 
function and none that the adjust- 
ment is essentially unlike the associa- 
tion between Glyptocrinus and Cy- 
clonema. The known facts regarding 
the combination are interesting. The 
starfish is Onychaster flexilis Meek 
and Worthen; it has rarely been 
found undetached. The crinoid 
seems most commonly to have been 
the high-domed species Actinocri- 
nus multiramosus. Waclismuth and 
Springer 1 tell of finding forty speci- 
mens of this crinoid in the Craw- 
fordsville shales of Indiana, of which 
nearly one-half had the attached 
starfish, and these authors were 
strongly disposed to the view that, 
because of the elevation of the anal 
tube and the situation of the waste 
aperture near its apex in a position seldom if ever cov- 
ered by the mouth of the starfish, the association was one 
of comfortable attachment only. Reference is made by 
the same writers to the fact that this starfish at the locali- 
i 1897, ‘ ‘ N. Amer. Crinoidea Camerata, ” p. 566. 
Fig 65. Tlie crinoid Acti- 
nocrinus multiramosus with 
a starfish (Onychaster) 
attached to the anal tube. 
(After Wachsmuth and 
Springer. ) 
