1885.] NATURAL SCIENCES OF PHILADELPHIA. 307 



for the true representatives of the basals. The presence of these 

 small pieces was also acknowledged by Meek and ourselves, but 

 Meek hesitating to call them basals, applied the name " sub- 

 basals;" while we took them to be rudimentary underbasals, and 

 as such the3 r have been described in Part II of the Revision, and 

 in our April paper. 



We have stated elsewhere, that in all Crinoids having basals 

 only, the column, when pentagonal, has its angles directed radi- 

 ally, the radii of the pentapetaloid or five rayed columnar canal 

 interradially, and that the opposite is the case in all species, 

 throughout all Palffiocrinoidea in which underbasals are present. 

 Applying this rule to Glyptocrinus and allied genera, we find that 

 every species referred by us to Glyptocrinus, is without under- 

 basals, and that all those, with one or two exceptions, which we 

 placed under Beteocrinus,h&ve underbasals. The exceptional spe- 

 cies are Glyptocrinus Richardsoni Wetherby, of which we speak 

 later on, and Meek's Glyptocrinus Baeri, which we found to be a 

 Xenocrinus, having four basals and a subquadrangular column ; 

 but, like Xenocrinus and Mariacrinus, a pentangular axial canal, 

 its angles directed strictly interradially. By carefully grinding off 

 the base in Gl. decadactylus, and in several other species, we have 

 become satisfied that the pieces which have been designated by 

 Hall, Meek and ourselves heretofore, respectively, as basals, sub- 

 basals, and rudimentary underbasals, form no part of the calyx, 

 but constitute the uppermost portion of the column, which in this 

 genus rests within a remarkably deep, funnel-shaped concavity. 



Among the species arranged by Miller under Glyptocrinus, and 

 which were said to have no underbasals, are Glyptocrinus Rich- 

 ardsoni Wetherby, and Gl. Pattersoni Miller. In Rev., Part II, 

 and subsequently in our paper in the Amer. Journal, these species 

 were placed under Reteocrinus Billings. In neither one of them 

 have underbasals been observed, although these plates may be 

 present, hidden beneath the column, as in the case of many Rho- 

 docrinidae and Poteriocrinidse. The species differ, however, very 

 materially from Gl. decadactylus and allied species without under- 

 basals in the distribution and position of their interradial plates, 

 which are irregularly arranged, and rest upon the five basals, ex- 

 actly as they do in Reteocrinus stellaris and in R. CfNealli, which, 

 contrary to the other species, have well developed underbasals. 

 The case is similar in Xenocrinus penicillus Miller, only that in 



