1869.] MEEK AND WORTHEN — ON PALAEOZOIC CRINOIDEA. 449 



to the genus Copuhis, may be supposed to have almost certainly 

 lived most of its life attached to one spot.* In such a case, why 

 should the Crinoid have so frequently left the Platyceras to grow 

 within its reach to nearly its adult size before devouring it ? 

 But if from some unknown cause it should have done so, by 

 what means could the Crinoid have pulled loose the Mollusk 

 (which, from analogy, we may reasonably suppose held with some 

 degree of tenacity to its place of attachment), and placed it with 

 the aperture of its shell over the opening supposed to be its own 

 mouth ? That it could have used its arms and tentacula as 

 prehensile organs, in this sense, is extremely improbable from 

 their very structure, so much so indeed that few if any of the 

 best authorities who have investigated the recent Crinoids, 

 believe that they ever used these appendages to hand directly to 

 the mouth, even minute organisms. f 



But we believe the strongest argument against the conclusion 

 that the Crinoids, so frequently found with the shell of a Platyceras 

 attached to them, died while in the act of sucking out, or other- 

 wise extracting the softer parts of these Mollusc, remains to be 

 stated. In the first place, if such really was the nature of the 

 relations between the Crinoid and the Mollusc, it is of course 



*Most of the best European authorities ou Palteontolof^y refer these 

 shells even to the existing genus Cupulas. 



tin many instances it is clearly evident that it would have been an 

 absolute impossibility for certain types of our Carboniferous Crinoids to 

 have handed any object, great or small, directly to the only opening 

 through the vault. That is, where this opening is at the extremity of a 

 straight rigid tube, often nearly twice the length of the arms, even to 

 the extreme ends of their ultimate divisions. We are aware that some 

 have supposed this tube, or proboscis, to have been flexible, and the 

 Messrs. Austin even thought it was especially designed and used for 

 the purpose of sucking out the softer parts of Polyps. If flexible, we 

 might suppose that in those cases where it was so much longer than the 

 arms, that it could have beeu curved so as to bring its extremity 

 within reach of the ends of the arms ; but although we have m a few 

 instances seen this tube more or less bent, a careful examination always 

 showed that, where this was not due to an accidental fracture after the 

 death of the animal, it was caused by the plates composing it being on 

 one side larger, or differently formed from those on the other, and 

 evidently not to flexibility. We find the arms, which were evidently 

 flexible, folded and beat in every conceivable manner, but the tube of 

 the vault is, in nine cases out often, if not more frequently, when not 

 accidentally distorted, found to be perfectly straight, or a little inclined 

 to one side or the other. 



