MELOCEINIDiE (Roemee) 1855. 



Monocyclic. Lower brachials, with well defined interbrachials between them, 



FORMING A PART OF THE DOESAL CUP. RaDIALS IN CONTACT ALL AROUND. 



Analysis of the Genera. 



I. 



The symmetry of the dorsal cup disturbed by one or more 



ANAL PLATES MeLOCRINITES. 



A. Basals five ; costals two. 



a. First costal hexagonal. 



Arms uniserial ; interbrachials and inter distichals numer- 

 ous. Ventral disk composed of very small, irregular 



plates. Basals small Glyptocrinus, 



Arms biserial, basals very large, otherwise resembling 



Glyptocrinus Periglyptocrinus. 



h. First costal quadrangular. 



Arms uniserial ; interbrachials few ; ventral disk com- 

 posed of large plates Stelidiocrinus. 



B. Basals four ; costals two. 



a. First costal hexagonal. 



Arms uniserial, arranged in groups ; simple or bifurcat- 

 ing, distichals two to four, calyx of moderate size . . Mariacrinus. 



Arms long, branching often ; palmars and arm joints 

 very short, deeply interlocking. Distichals five and 

 upwards. Calyx very large; lower palmars partly in- 

 cluded in dorsal cup, interbrachials very numerous . Scyphocrinus. 



The rays extended into five tubular trunks, from which 

 biserial arms are given off from the outer sides all the 

 w^ay to their tips Melocrinus. 



C. Basals three ; costals two. 



Arms biserial, simple from their origin; interbrachials 



few, an anal plate interposed within the first range . Macrostylocrinus. 



II. 



Symmetry of dorsal cup undisturbed by anal plates .... Dolatocrinites. 



A. Basals four; costals two. 



a. Arms biserial. 



Arms simple ; arranged equilaterally around the calyx ; 



base obconical Technocrinus. 



Arms dichotomous ; basal cup inverted ; interbrachials 



large Corymhocrinus. 



B. Basals three, small ; costals two, the first quadrangular. 



a. Arms simple. 



