1885.] NATURAL SCIENCES OF PHILADELPHIA. 311 



recognizing them as a distinct family, -which we propose to call 

 Reteocrinidae. 



Now, having referred the genus Glyptocrinus in its typical 

 form, and " Glyptocrinus" (Compsocrinus) Harrisi Miller,— Ma- 

 riacrinus Harrisi, to the Actinocrinidse or their allies, Reteocri- 

 wws, Xenocrinus, and our new genus Canistocrinus to the Rtteo- 

 crinidse, there remain for consideration among species with under- 

 basals, or Rhodocrinidae,as they were previously called, two other 

 groups : 



(a.) Species, in which all five primary interradials meet the 

 basals, forming a ring of ten plates with the first radials. 



(6.) Species, in which the first anal plate only rests upon the 

 basals, the interradials upon the edges of the first radials. The 

 first group comprises the genera : Archseocrinus, our new genus 

 Rhaphanocrinus, Lyriocrinus, Rhipidocrinus, Tlnjlacoerinus, An- 

 themocrirms, Rhodocrinus, and Ollacrinus; the second Glyptaster, 

 DimerocrinuSj Ptychocrinus and Lavipterocrinus. The former 

 group agrees with our subdivision Rhodocrinites, except Archse- 

 ocrinus, which we had previously arranged under Glyptocrinites ; 

 the latter corresponds with our former Glyptasterites. 



It might be as well, perhaps, to let these groups remain as sub- 

 divisions of the Rhodocrinidae ; but, as it is desirable that the 

 families proposed by various authors in the different classifica- 

 tions should be made to correspond as far as possible, we follow 

 Zittel, and rank them as full families. The first, as embracing 

 the t3'pical genus, will be Rhodocrinidse. Zittel's name, Glypto- 

 crinidae, however, cannot be used for the other group, since it is 

 known that Glyptocrinus has no underbasals. We propose in its 

 place the name Glyptasteridae, Glyptaster being one of its most 

 characteristic types. 



These divisions are substantially in conformitj' with the views 

 of Carpenter, expressed in his paper on Thaumatocrinus, p. 929. 

 He approves ZitteFs division into Glyptocrinidae and Rhodocrini- 

 dse, but acknowledges at the same time ''that Glyptocrinus has de- 

 cided affinities with the Actinocrinidae." His views upon the irregu- 

 lar plates of Reteocrinus have alreadj' been quoted. The rounded 

 ridges along the radials, as they appear in Reteocrinus and Xeno- 

 crinus, are more than mere ornamentations. They seem to have 

 contained tubular passages which, perhaps, may represent the axial 

 canals, while the more angular ridges of Glyptocrinus, Glyptaster 7 



