1885.] NATURAL SCIENCES OP PHILADELPHIA. 255 



Haplocrinus nor other Palaeocrinoidea, for the proximals which 

 Carpenter takes to be the representatives of the orals, are per- 

 manently closed, with the exception of Coccocrinus, in which the 

 "orals " are said to be parted, bnt in which the central plate is 

 wanting. 



Another difficulty is offered by the fact that the so-called 

 " oral " plates are pierced b} r the anal opening, a structure which 

 certainly has no parallel among recent Crinoids. 



Allagecrinus was described by Etheridge and Carpenter (Ann. 

 and Mag. Nat. Hist., April, 1881) as without central piece, and 

 the latter has since informed us, that he could not identify any 

 such plate on re-examining the specimens. This, however, does 

 not prove that it was wanting, for we must bear in mind that 

 Allagecrinus Austinii is an almost microscopic form, not larger 

 than a coarse grain of sand. The central piece was overlooked 

 by the European naturalists, in the much larger Haplocrinus. 

 Goldfuss, however, observed in (Eugeniacrinites) Haplocrinus 

 mespiliformis (Petref. Germ., i, p. 214) " ein rundes Knopfchen 

 im Scheitelpunkt," and it is very significant that Etheridge and 

 Carpenter also found in Allagecrinus " at the central end of one 

 or more of the plates faint tubercles," for which, according to 

 their own statement, " they can find no explanation." Whether 

 these represent the tubercles which we discovered upon the face 

 of the interraclials in Cyathocrinus multiradiatus (PI. 4. fig. 2), 

 we are of course not prepared to assert with certainty, but it is 

 worthy of note that Carpenter regards the latter " as the conical 

 openings in Granatocrinus Norivordi^ 1 and it is very possible 

 that they are the same thing in all three groups, w 7 hich would 

 prove better than anything else, that the plates bearing them are 

 not orals but interradials. The tubercles in Allagecrinus (com- 

 pare Ann. and Mag., ser. 5, vol. 7, PI. xvi, figs. 3 &, 4, 5 and lb), 

 are evidently of structural value, but as there is but one figured, 

 although the description speaks of one to each plate, and this is 

 located laterally in one specimen and centrally in the other, all 

 interpretations by us must necessarily be more or less problemat- 

 ical. We are inclined, however, to believe that the lateral one (fig. 

 5), in analogy with Haplocrinus, represents the anal opening, i. e. 



1 This suggestion was made by Dr. P. Herb. Carpenter in his letter of 

 Decembi r 26, after sending him our figures, and he kindly permitted us to 

 make use of it in our writings. 



