KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 2. 65 



E a c h i r o c r i n u s, Meek and Wortiien. 



r. post. R s and r. ant. R s fused into a T-piece, which abuts with either wing on 

 corners of large RR: x supported by wliole upper margin of T-piece: R' and r. ant. R' 

 geparated from one another and from x by T-piece. 



Concomitant chara eters: BB nnfused (? sometimes I. post. B and 1. ant. B fnsed), 

 all entering into articulation of stem; post; B and r. ant. B are böunded for 1 ., or ' 2 of 

 their onter margins by large RR. 1. ant. R s joined to 1. ant. R' by suture and does not 

 project above level of large RR. Arms 3. 



Type: E. chrySaMs, Hall sp. 

 Calceocrinus, (Hall) Ringueberg. 



T-piece (fnsed r. post. K s and r. ant. R s ) separated by R' and r. ant. R' from large 

 RR; it is low, wide and sometimes very small: x supported by both T-piece and R' and 

 r. ant. R', hut does not touch large RR. 



Concomitant chara eters: 1. post. B and 1. ant. B fused; this fnsed B never, or 

 verv rardy, enters into stem-articulation; post. B and r. ant. B bttur/ded for abont half 

 their onter margins by large RR: 1. ant. R* and 1. ant. 1!' are two triangnlar plates rneeting 

 at their apices or entirely separated by large RR. R and r. ant. R' stated to be, in some 

 cases, fnsed with large RR. Arms 3. 



Type: C. typus, Ringueberg. 

 Halysiocrinus, (Ulrich) Bather. 



T-piece (fused r. post. R* and r. ant. R s ) either completely atrophied br ludden be- 

 tween R', r. ant. R' and BB in stem-articulation. x supported by R' and r. ant. R', which 

 ha ve now met, and abuts by its lower corners on large \\\\. 



Concomitant characters: BB as in ualöäöcHnifs (? sometimes post. B and r\ ant. B 

 also fnsed); the fused 1. post. B and 1. ant. B never enter into stem-articnlation; post. B 

 and r. ant. B bounded for ahout 8 /s their onter margins by large RR. 1. ant. R* and 

 1. ant. R' always completelv separated by large RR. R' and r. ant. R' perhaps fused with 

 large RR in some cases. Arms 3. 



Type: H. ventricosus, Hall sp. (? = H. äaciylids, Hall sp.). 



Sinee these four genera represent an evolutionary series, and not divergent branches, 

 it is to be expected that raany forms should be of an intermediate nature, and t hat there 

 should be some difSculty in referring thera to one or the other genus. Thus, it will be 

 seen that some of the Gotland Calceocrihi approaeh Euchirocrinus, while others are not 

 lar removed from Halysiocrinus. The American spccies of Devonian age will probably 

 present grcater difficulties. As I have not had the opportnnity of stuaying these or the 

 other Carboniferous species, I cannot undertakc to refor any of thcm to Halysiocrinus; 

 hut I hope that, with the diagnoses above given, American palreontologists will be able 

 to deterraine their respective genera without further trouble than that of preparing those 

 sjieeimens which they have already found. 



The following is believed to be a complete List of the Species of the Calceocrinida 1 

 hitherto named. In assigning them to their respecti\ c genera I have been guided, in the 



K Sv Vet. Akad Handl. Band. 2"). N:o 2. 9 



