444 SMITHSONIAN INSTITUTION 



reaffirmed as to speciesin 1913, declared it to be a dicyclic crinoid, with fused infrabasals 

 and five basals, — all of which statements must now be corrected. 



When proposing the genus in 1859 1 Hall defined the elements of the calyx as follows : 



Base solid, without division into plates : upper margin marked by six angles, with depressions between 

 for insertion of radial plates. Radial plates five, inserted in the five larger depressions on the upper 

 edge of the calyx. Anal plates two, the lower one inserted in the smaller of the six impressions (p. 119). 



Based upon specimens of E. sac cuius from the Oriskany of Maryland he stated that — 



These crinoids are sessile in the young state, adhering singly or in groups to other substances until 

 fully developed, when they are separated from the foreign bodies, and, gradually secreting calcareous 

 matter to cover the cicatrix or point of adhesion, become finally the smoothly rounded bases which we 

 find so numerously (p. 120). 



In the Revision of the Palaeocrinoidea, Pt. I, 1879, p. 21, Wachsmuth and Springer 

 referred to the calyx of Edriocrinus as being attached when young, and in maturity becom- 

 ing free; and in Pt. Ill, 1886, p. 262, we placed it provisionally under the Astylocrinidae 

 along with other free-floating crinoids, saying that it " in all probability, forms a family by 

 itself, being sessile in early life, and having no underbasals." 



Bather in May, 1890, - listed Edriocrinus as a form which is " so extremely special- 

 ized .... that one cannot perceive its true affinities " ; and in the Lankester Zoology, 1900, 

 p. 191, he placed the genus provisionally in the Flexibilia Impinnata, giving the characters 

 as follows : 



When young is attached by BB, but is free-floating in adult ; BB become fused into a bowl-shaped 

 mass, supporting 5 RR and x; arms broad, with low Br, isotomous. 



Such was the state of opinion as to the characters of the genus until 1905, when Miss 

 Mignon Talbot in a Revision of the New York Helderbergian Crinoids 3 proposed a new 

 family for its reception, rejecting the systematic references of the genus by Wachsmuth and 

 Springer and by Bather, saying as to the latter — 



Bather lists the genus provisionally under the order Flexibilia, an order with no anal plate in the 

 cup( !) ; but as Edriocrinus has such a plate, the genus cannot be so referred (p. 22). 



Her family diagnosis is in part as follows : 



Base dicyclic, probably 5 fused plates in each order .... attachment being by the infrabasals in the 

 young stages ; mature forms unattached. 



In the course of a discussion of the characters of the genus, based chiefly upon speci- 

 mens of E. pocilliformis from New York, some of which are figured upon the accompanying 

 plate 4, figures 1-6, the author states that specimens No. 2 and No. 5, "instead of being 

 monocyclic are dicyclic," and that "No. 3 shows infrabasals and basals" (p. 21). As the 

 result of these observations she gives an amended diagnosis, of which the part material to 

 the present inquiry reads as follows : 



Amended generic description. — Calyx directly cemented, either throughout life or only in the young 

 stages, the attachment being by the large infrabasals. The cicatrix very large in some specimens and in 

 others obliterated, by the accumulation of calcareous matter on the outer surface of the calyx plates. 

 Infrabasals large, their height being from one-half to two-thirds that of the cup as ordinarily found, 

 completely fused so as to destroy suture lines and to make the number of plates uncertain. Basals five, 

 height varying in proportion to that of the infrabasals, generally so fused as to show no suture lines on 

 the outer surface, although they are often seen on the inner side. 



In conformity with this, the specific description which follows contains the same state- 

 ments : — " Infrabasals present .... Basals five." 



It is unfortunate that so material an addition as that of infrabasals and a definite num- 



*Nat. Hist. N. Y. Pal. Ill, 1859, pp. 119-121, 143. 



'' Ann. and Mag. N. H. (6) V, p. 379. 



3 Am. Journ. Sci. (4) XX, July, 1905, pp. 17-33, Plates I-IV. 



