102 PROCEEDINGS OP THE ACADEMY OP [1886. 



A very different interpretation of the so-called consolidating 

 apparatus has been given to us by Dr. P. H. Carpenter, who 

 regards it as representing the united muscle-plates of the radials. 

 He wrote to us as follows : " I look upou the consolidating 

 apparatus as offering a surface for the attachment of muscles by 

 which the arms were moved on the calyx. The successive arm- 

 pieces I will not call them 'joints ' were suturally united and not 

 movable upon one another, so that the arms were moved en masse 

 upon the calyx, and this must have required very strong muscles 

 between the calyx and first brachials. All that is ordinarily 

 supposed to represent the articular face of the radials is shown 

 in Schultze's Taf. II, fig. 5 a, while that of the arm-base appears 

 on fig. 7 b. Now, it appears to me improbable that the heavy, 

 massive arms of Gupressocrinus were moved by muscles which 

 had no further surface of attachment at their proximal end, at 

 any rate than is shown in Fig. 5 a. Symbathocrinus has large 

 muscle-plates, but there is nothing of this kind in Gupressocrinus, 

 without the consolidating plates. The calyx of Phimocrinus Isevis 

 (Schultze, Taf. Ill, fig. 6 a), corresponds to that of Gupresso- 

 crinus, with the consolidating plates in situ. There is the same 

 arrangement round the anal opening, of which there is absolutely 

 no trace in Gupressocrinus, without the consolidating plates, and 

 yet it is clear from Schultze's description that he regards (rightly 

 as I believe) the top of the calyx to be formed of the ' Gelenk- 

 flachen der Radialia,' with the anus between two of them. I 

 cannot, therefore, help regarding the consolidating apparatus of 

 Gupressocrinus as consisting of the united muscles-plates of the 

 radials, from the lower portions of which they are apt to 

 separate." This seems to us a very reasonable solution of the 

 question, and we fully agree with Carpenter. We have since 

 found that the plates are not interradially disposed, nor do they 

 form separate pieces ; the sutures which we thought we observed 

 are evidently radial sinuses, similar to those which we described 

 in Symbathocrinus. 



The arm structure of Gupressocrinus was also poirvted out 

 more accurately by Goldfuss than b}^ most of the succeeding 

 writers. The outer and inner " Querbalken " of Schultze (Mon., 

 PL l,figs. 1 /i, a, 13), are obviously the basal portions of incurved 

 pinnules, and as such they were described and figured by Zittel. 

 These pinnules, however, in the opinion of Carpenter, are not 



