of the Crinoidea brachiata. 



405 



Melocrmux. 



as the annexed figure shows, from the right adjacent radius to 

 the left abjacent interradius, 

 and is theretbre turned further 

 from the radial axis by one de- 

 cimal space. 



The observation was made 

 on twenty calyces, partly be- 

 longing to M. hieroglyphiciiSj 

 from Stolberg, and ])artly to 

 undescribed tjppcr Devonian 

 species fi'om Senseille, near 

 Couvin, in Belgium. In seven- 

 teen calyces the normal divi- 

 sion appeared ; in the other 

 three it deviated in the same 

 way — namely, so that the dorsal axis coincided with the radial. 



If a dlcijcllc qwadripartite base were divided in accordance 

 with the same axis as the mo- 

 nocyclic base of Melocrimts, and 

 therefore stood in the same re- 

 lation to this as the base of the 



Taxocrinida3 to that of Platy- / \ ^^ 



criniis, the segments of the 

 inferior basal circle would be 

 placed as in the annexed figure. 

 A base divided in this manner 

 has not yet been observed, but 

 it has to be taken into con- 

 sideration in the examination 

 of the structure of the genus 

 Cupressocrin us. 



Cuj)ressocrim(S has perfectly regularly constructed radii, 

 without intcrradial plates. The ventral covering is unknown ; 

 but the internal framework, extended between the radii, which 

 is peculiar to the genus, possesses an interradially placed 

 aperture, indicating the position of the vertical aperture — by 

 means of which we are enabled to regard the calyx as divided 

 in accordance with a radial axis, and therefore also to discuss 

 the question whether the quadriradiate division of the stem, 

 which occurs in most species of the genus, stands in the same 

 relations to the radial division of the calyx as the division of- 

 the base in other genera. 



The dicyclically constituted base of Cupressocrinus consists 

 of a regularly quinquepartite upper circle and an undivided 

 central plate, which sometimes extends flatly beyond the end 

 of the stem, sometimes is erected for a short distance, and 



