CALAMOCRINUS DIOMEDiE. 



;nul thai the} soon assume their ultimate shape, gradually passing into the 

 lower joints where the joints are identical, or nearlj so, while in the 

 upper part, where new joints are formed, the} are not Beyrich and 

 von Koenen seem to have succeeded in tracings regular order of appear- 

 ance of the new joints. I could only say thai from three to four new 

 joints are intercalated between anj two original sutures of thai pi 

 the stem where they are added by the gradual increase in height. I 

 cannot understand why Beyrich asserts [loc. cit., p. 7) thai in the youngesl 

 the stem could be divided into two parts, in one of which the. 

 lower joints never possessed the flat shape of the young joints of the 

 upper extremity, ami via versa. This certainly is not the ease in Calamo- 

 crinus, and there seems to be no valid reason for the interpretation given 

 by Beyrich to the difference in structure lie observed in the upper and 

 lower parts of the stem of Encrinus. 



Hall figures* the upper part of the stem of Dendrocrinus longidactylus, 

 showing plainly the new joints forcing their way to the surface between 

 the older ones. 



In [chthyocrinus young joints appear to be most numerous also in the 

 part of the stem immediately below the calyx. 



In Poteriocrinu<. Cyathocrinus, Platycrinus, Actinocrinus. and other 

 palaeozoic Crinoids, the same is the case, so far as can be judged from 

 the numerous figures of parts of the stem which have been published in 

 the Palaeontologies of New York, of Illinois, of Iowa, and of Ohio, and by 

 Angelin, 



De Koninck and Le Hon t figure a stem joint of Poteriocrinus showing 

 the same structure of the axial part of the stem which we find in the 

 upper joints of Calamocrinus. 



In the descriptions and figures of Crinoids given by Hall and Whitfield 

 of the Crinoids of the Waverly group (Geol. Survey of Ohio. Palaeontology, 

 Vol. II. Plate XI.), the upper part of the column of Actinocrinus consists 

 of alternating or of uniform joints, soon passing into a region of the column 

 in which the joints are alternately thick and thin, and rapidly passing to 

 thick joints separated bj r three or four thinner joints, which in their turn 

 may be wide or narrow, the thicker joints projecting beyond the edge of 

 the column. 



* Paleontology of Xew York. Vol. II. Plate 42. Figs. 7. 7>\ 



f De Koninck and Le Hon, Crinoides du Terrain Carbonifeie de la Belgique, 1854, Plate I. Fig. 1. 



